drm/panel: panel-simple: Fix 'struct panel_desc's header

Struct headers should start with 'struct <name>'

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

 drivers/gpu/drm/panel/panel-simple.c:42: warning: Cannot understand  * @modes: Pointer to array of fixed modes appropriate for this panel.  If

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
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>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105144517.1826692-12-lee.jones@linaro.org

drivers/gpu/drm/panel/panel-simple.c

@@ -39,6 +39,7 @@
 #include <drm/drm_panel.h>
 
 /**
+ * struct panel_desc
  * @modes: Pointer to array of fixed modes appropriate for this panel.  If
  *         only one mode then this can just be the address of this the mode.
  *         NOTE: cannot be used with "timings" and also if this is specified
@@ -53,6 +54,7 @@
  * @delay: Structure containing various delay values for this panel.
  * @bus_format: See MEDIA_BUS_FMT_... defines.
  * @bus_flags: See DRM_BUS_FLAG_... defines.
+ * @connector_type: LVDS, eDP, DSI, DPI, etc.
  */
 struct panel_desc {
 	const struct drm_display_mode *modes;