drm/fb: Extend format_info member arrays to handle four planes

addfb() uAPI has supported four planes for a while now, make format_info
compatible with that.

Cc: Ville Syrjälä <[e-mail]>
Cc: Matt Roper <[e-mail]>
Cc: Mika Kahola <[e-mail]>
Cc: [e-mail]
Signed-off-by: Dhinakaran Pandiyan <[e-mail]>
Signed-off-by: Imre Deak <[e-mail]>
Reviewed-by: Mika Kahola <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

include/drm/drm_fourcc.h

···
 		 * triplet @char_per_block, @block_w, @block_h for better
 		 * describing the pixel format.
 		 */
-		u8 cpp[3];
+		u8 cpp[4];
 
 		/**
 		 * @char_per_block:
···
 		 * information from their drm_mode_config.get_format_info hook
 		 * if they want the core to be validating the pitch.
 		 */
-		u8 char_per_block[3];
+		u8 char_per_block[4];
 	};
 
 	/**
···
 	 * Block width in pixels, this is intended to be accessed through
 	 * drm_format_info_block_width()
 	 */
-	u8 block_w[3];
+	u8 block_w[4];
 
 	/**
 	 * @block_h:
···
 	 * Block height in pixels, this is intended to be accessed through
 	 * drm_format_info_block_height()
 	 */
-	u8 block_h[3];
+	u8 block_h[4];
 
 	/** @hsub: Horizontal chroma subsampling factor */
 	u8 hsub;