Input: document intended meaning of KEY_SWITCHVIDEOMODE

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

include/linux/input.h

@@ -344,7 +344,8 @@ struct input_absinfo {
 #define KEY_BRIGHTNESSUP	225
 #define KEY_MEDIA		226
 
-#define KEY_SWITCHVIDEOMODE	227
+#define KEY_SWITCHVIDEOMODE	227	/* Cycle between available video
+					   outputs (Monitor/LCD/TV-out/etc) */
 #define KEY_KBDILLUMTOGGLE	228
 #define KEY_KBDILLUMDOWN	229
 #define KEY_KBDILLUMUP		230