drm: panel: simple: Fixup the struct panel_desc kernel doc

When I run:
  scripts/kernel-doc -rst drivers/gpu/drm/panel/panel-simple.c

I see that several of the kernel-doc entries aren't showing up because
they don't specify the full path down the hierarchy.  Let's fix that
and also move to inline kernel docs.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201109170018.v4.1.Icaa86f0a4ca45a9a7184da4bc63386b29792d613@changeid

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

@@ -64,33 +64,58 @@ struct panel_desc {
 
 	unsigned int bpc;
 
-	/**
-	 * @width: width (in millimeters) of the panel's active display area
-	 * @height: height (in millimeters) of the panel's active display area
-	 */
 	struct {
+		/**
+		 * @size.width: Width (in mm) of the active display area.
+		 */
 		unsigned int width;
+
+		/**
+		 * @size.height: Height (in mm) of the active display area.
+		 */
 		unsigned int height;
 	} size;
 
-	/**
-	 * @prepare: the time (in milliseconds) that it takes for the panel to
-	 *           become ready and start receiving video data
-	 * @hpd_absent_delay: Add this to the prepare delay if we know Hot
-	 *                    Plug Detect isn't used.
-	 * @enable: the time (in milliseconds) that it takes for the panel to
-	 *          display the first valid frame after starting to receive
-	 *          video data
-	 * @disable: the time (in milliseconds) that it takes for the panel to
-	 *           turn the display off (no content is visible)
-	 * @unprepare: the time (in milliseconds) that it takes for the panel
-	 *             to power itself down completely
-	 */
 	struct {
+		/**
+		 * @delay.prepare: Time for the panel to become ready.
+		 *
+		 * The time (in milliseconds) that it takes for the panel to
+		 * become ready and start receiving video data
+		 */
 		unsigned int prepare;
+
+		/**
+		 * @delay.hpd_absent_delay: Time to wait if HPD isn't hooked up.
+		 *
+		 * Add this to the prepare delay if we know Hot Plug Detect
+		 * isn't used.
+		 */
 		unsigned int hpd_absent_delay;
+
+		/**
+		 * @delay.enable: Time for the panel to display a valid frame.
+		 *
+		 * The time (in milliseconds) that it takes for the panel to
+		 * display the first valid frame after starting to receive
+		 * video data.
+		 */
 		unsigned int enable;
+
+		/**
+		 * @delay.disable: Time for the panel to turn the display off.
+		 *
+		 * The time (in milliseconds) that it takes for the panel to
+		 * turn the display off (no content is visible).
+		 */
 		unsigned int disable;
+
+		/**
+		 * @delay.unprepare: Time to power down completely.
+		 *
+		 * The time (in milliseconds) that it takes for the panel
+		 * to power itself down completely.
+		 */
 		unsigned int unprepare;
 	} delay;