drm/connector: document DRM_MODE_COLORIMETRY_COUNT

The drm_colorspace enum member DRM_MODE_COLORIMETRY_COUNT has been
properly documented by moving the description out of the enum to the
member description list to get rid of an additional warning and improve
documentation clarity.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230906-topic-drm_connector_doc-v2-1-1f2dcaa43269@gmail.com

Author: javiercarrascocruz

include/drm/drm_connector.h

@@ -498,6 +498,8 @@ enum drm_privacy_screen_status {
  *   ITU-R BT.601 colorimetry format
  *   The DP spec does not say whether this is the 525 or the 625
  *   line version.
+ * @DRM_MODE_COLORIMETRY_COUNT:
+ *   Not a valid value; merely used four counting
  */
 enum drm_colorspace {
 	/* For Default case, driver will set the colorspace */
@@ -522,7 +524,6 @@ enum drm_colorspace {
 	DRM_MODE_COLORIMETRY_RGB_WIDE_FIXED	= 13,
 	DRM_MODE_COLORIMETRY_RGB_WIDE_FLOAT	= 14,
 	DRM_MODE_COLORIMETRY_BT601_YCC		= 15,
-	/* not a valid value; merely used for counting */
 	DRM_MODE_COLORIMETRY_COUNT
 };