drm: Fix kernel docs for drm_helper_mode_fill_fb_struct()

drm_modeset_helper.c:74: warning: No description found for parameter 'dev'

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Fixes: a3f913ca9892 ("drm: Pass 'dev' to drm_helper_mode_fill_fb_struct()")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161215170128.23972-1-ville.syrjala@linux.intel.com
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/drm_modeset_helper.c

@@ -62,6 +62,7 @@ EXPORT_SYMBOL(drm_helper_move_panel_connectors_to_head);
 
 /**
  * drm_helper_mode_fill_fb_struct - fill out framebuffer metadata
+ * @dev: DRM device
  * @fb: drm_framebuffer object to fill out
  * @mode_cmd: metadata from the userspace fb creation request
  *