Input: add SW_MUTE_DEVICE switch definition

Some devices, such as new Intuos series tablets, have a hardware switch to
turn touch data on/off. To report the state, SW_MUTE_DEVICE is added
in include/uapi/linux/input.h.

Reviewed_by: Chris Bagwell <chris@cnpbagwell.com>
Acked-by: NPeter Hutterer <peter.hutterer@who-t.net>
Tested-by: NJason Gerecke <killertofu@gmail.com>
Signed-off-by: NPing Cheng <pingc@wacom.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

include/uapi/linux/input.h

@@ -858,6 +858,7 @@ struct input_keymap_entry {
 #define SW_FRONT_PROXIMITY	0x0b  /* set = front proximity sensor active */
 #define SW_ROTATE_LOCK		0x0c  /* set = rotate locked/disabled */
 #define SW_LINEIN_INSERT	0x0d  /* set = inserted */
+#define SW_MUTE_DEVICE		0x0e  /* set = device disabled */
 #define SW_MAX			0x0f
 #define SW_CNT			(SW_MAX+1)