drm/vmwgfx/vmwgfx_surface: Fix some kernel-doc related issues

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:55: warning: Function parameter or member 'prime' not described in 'vmw_user_surface'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:55: warning: Function parameter or member 'backup_base' not described in 'vmw_user_surface'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:78: warning: cannot understand function prototype: 'struct vmw_surface_dirty '
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'header' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'body' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'cb' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'suffix' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:181: warning: Function parameter or member 'header' not described in 'vmw_surface_define'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:181: warning: Function parameter or member 'body' not described in 'vmw_surface_define'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:189: warning: Function parameter or member 'header' not described in 'vmw_surface_destroy'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:189: warning: Function parameter or member 'body' not described in 'vmw_surface_destroy'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:555: warning: Function parameter or member 'readback' not described in 'vmw_legacy_srf_unbind'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:1067: warning: Function parameter or member 'res' not described in 'vmw_gb_surface_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:1067: warning: Excess function parameter 'srf' description in 'vmw_gb_surface_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:1067: warning: Excess function parameter 'cmd_space' description in 'vmw_gb_surface_create'

Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Roland Scheidegger <sroland@vmware.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210115181313.3431493-34-lee.jones@linaro.org

drivers/gpu/drm/vmwgfx/vmwgfx_surface.c

@@ -41,10 +41,12 @@
 /**
  * struct vmw_user_surface - User-space visible surface resource
  *
+ * @prime:          The TTM prime object.
  * @base:           The TTM base object handling user-space visibility.
  * @srf:            The surface metadata.
  * @size:           TTM accounting size for the surface.
- * @master: master of the creating client. Used for security check.
+ * @master:         Master of the creating client. Used for security check.
+ * @backup_base:    The TTM base object of the backup buffer.
  */
 struct vmw_user_surface {
 	struct ttm_prime_object prime;
@@ -69,7 +71,7 @@ struct vmw_surface_offset {
 };
 
 /**
- * vmw_surface_dirty - Surface dirty-tracker
+ * struct vmw_surface_dirty - Surface dirty-tracker
  * @cache: Cached layout information of the surface.
  * @size: Accounting size for the struct vmw_surface_dirty.
  * @num_subres: Number of subresources.
@@ -162,7 +164,7 @@ static const struct vmw_res_func vmw_gb_surface_func = {
 	.clean = vmw_surface_clean,
 };
 
-/**
+/*
  * struct vmw_surface_dma - SVGA3D DMA command
  */
 struct vmw_surface_dma {
@@ -172,7 +174,7 @@ struct vmw_surface_dma {
 	SVGA3dCmdSurfaceDMASuffix suffix;
 };
 
-/**
+/*
  * struct vmw_surface_define - SVGA3D Surface Define command
  */
 struct vmw_surface_define {
@@ -180,7 +182,7 @@ struct vmw_surface_define {
 	SVGA3dCmdDefineSurface body;
 };
 
-/**
+/*
  * struct vmw_surface_destroy - SVGA3D Surface Destroy command
  */
 struct vmw_surface_destroy {
@@ -544,6 +546,7 @@ static int vmw_legacy_srf_bind(struct vmw_resource *res,
  *
  * @res:            Pointer to a struct vmw_res embedded in a struct
  *                  vmw_surface.
+ * @readback:       Readback - only true if dirty
  * @val_buf:        Pointer to a struct ttm_validate_buffer containing
  *                  information about the backup buffer.
  *
@@ -1060,8 +1063,8 @@ int vmw_surface_reference_ioctl(struct drm_device *dev, void *data,
 /**
  * vmw_surface_define_encode - Encode a surface_define command.
  *
- * @srf: Pointer to a struct vmw_surface object.
- * @cmd_space: Pointer to memory area in which the commands should be encoded.
+ * @res:        Pointer to a struct vmw_resource embedded in a struct
+ *              vmw_surface.
  */
 static int vmw_gb_surface_create(struct vmw_resource *res)
 {