drm/nouveau/nvkm/core/firmware: Fix formatting, provide missing param description

... and demote non-conformant kernel-doc header.

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

 drivers/gpu/drm/nouveau/nvkm/core/firmware.c:71: warning: Function parameter or member 'subdev' not described in 'nvkm_firmware_get'
 drivers/gpu/drm/nouveau/nvkm/core/firmware.c:71: warning: Function parameter or member 'fwname' not described in 'nvkm_firmware_get'
 drivers/gpu/drm/nouveau/nvkm/core/firmware.c:71: warning: Function parameter or member 'ver' not described in 'nvkm_firmware_get'
 drivers/gpu/drm/nouveau/nvkm/core/firmware.c:71: warning: Function parameter or member 'fw' not described in 'nvkm_firmware_get'
 drivers/gpu/drm/nouveau/nvkm/core/firmware.c:106: warning: Function parameter or member 'fw' not described in 'nvkm_firmware_put'

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201116174112.1833368-22-lee.jones@linaro.org

drivers/gpu/drm/nouveau/nvkm/core/firmware.c

@@ -58,9 +58,10 @@ nvkm_firmware_load_blob(const struct nvkm_subdev *subdev, const char *base,
 
 /**
  * nvkm_firmware_get - load firmware from the official nvidia/chip/ directory
- * @subdev	subdevice that will use that firmware
- * @fwname	name of firmware file to load
- * @fw		firmware structure to load to
+ * @subdev:	subdevice that will use that firmware
+ * @fwname:	name of firmware file to load
+ * @ver:	firmware version to load
+ * @fw:		firmware structure to load to
  *
  * Use this function to load firmware files in the form nvidia/chip/fwname.bin.
  * Firmware files released by NVIDIA will always follow this format.
@@ -98,7 +99,7 @@ nvkm_firmware_get(const struct nvkm_subdev *subdev, const char *fwname, int ver,
 	return -ENOENT;
 }
 
-/**
+/*
  * nvkm_firmware_put - release firmware loaded with nvkm_firmware_get
  */
 void