drm/vmwgfx/vmwgfx_scrn: Demote unworthy kernel-doc headers and update others

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

 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:90: warning: cannot understand function prototype: 'struct vmw_screen_object_unit '
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:122: warning: Function parameter or member 'dev_priv' not described in 'vmw_sou_fifo_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:122: warning: Function parameter or member 'sou' not described in 'vmw_sou_fifo_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:122: warning: Function parameter or member 'x' not described in 'vmw_sou_fifo_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:122: warning: Function parameter or member 'y' not described in 'vmw_sou_fifo_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:122: warning: Function parameter or member 'mode' not described in 'vmw_sou_fifo_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:168: warning: Function parameter or member 'dev_priv' not described in 'vmw_sou_fifo_destroy'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:168: warning: Function parameter or member 'sou' not described in 'vmw_sou_fifo_destroy'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:283: warning: Function parameter or member 'state' not described in 'vmw_sou_crtc_atomic_enable'
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c:293: warning: Function parameter or member 'state' not described in 'vmw_sou_crtc_atomic_disable'

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/20210115181313.3431493-30-lee.jones@linaro.org

drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c

@@ -84,7 +84,7 @@ struct vmw_kms_sou_define_gmrfb {
 	SVGAFifoCmdDefineGMRFB body;
 };
 
-/**
+/*
  * Display unit using screen objects.
  */
 struct vmw_screen_object_unit {
@@ -112,7 +112,7 @@ static void vmw_sou_crtc_destroy(struct drm_crtc *crtc)
 	vmw_sou_destroy(vmw_crtc_to_sou(crtc));
 }
 
-/**
+/*
  * Send the fifo command to create a screen.
  */
 static int vmw_sou_fifo_create(struct vmw_private *dev_priv,
@@ -160,7 +160,7 @@ static int vmw_sou_fifo_create(struct vmw_private *dev_priv,
 	return 0;
 }
 
-/**
+/*
  * Send the fifo command to destroy a screen.
  */
 static int vmw_sou_fifo_destroy(struct vmw_private *dev_priv,
@@ -275,6 +275,7 @@ static void vmw_sou_crtc_helper_prepare(struct drm_crtc *crtc)
  * vmw_sou_crtc_atomic_enable - Noop
  *
  * @crtc: CRTC associated with the new screen
+ * @state: Unused
  *
  * This is called after a mode set has been completed.
  */
@@ -287,6 +288,7 @@ static void vmw_sou_crtc_atomic_enable(struct drm_crtc *crtc,
  * vmw_sou_crtc_atomic_disable - Turns off CRTC
  *
  * @crtc: CRTC to be turned off
+ * @state: Unused
  */
 static void vmw_sou_crtc_atomic_disable(struct drm_crtc *crtc,
 					struct drm_atomic_state *state)