Input: add keycodes for touchpad on/off keys

Some laptops will have a "touchpad toggle" soft button, which expects
user-space to turn off the touchpad themselves, some other devices will
do this in hardware, but send key events telling us that the touchpad
has been turned off/on.

KEY_TOUCHPAD_ON/KEY_TOUCHPAD_OFF will be used by user-space to show a
popup with the status of the touchpad.
Signed-off-by: NBastien Nocera <hadess@hadess.net>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

include/linux/input.h

@@ -624,6 +624,10 @@ struct input_keymap_entry {
 #define KEY_CAMERA_FOCUS	0x210
 #define KEY_WPS_BUTTON		0x211	/* WiFi Protected Setup key */
 
+#define KEY_TOUCHPAD_TOGGLE	0x212	/* Request switch touchpad on or off */
+#define KEY_TOUCHPAD_ON		0x213
+#define KEY_TOUCHPAD_OFF	0x214
+
 #define BTN_TRIGGER_HAPPY		0x2c0
 #define BTN_TRIGGER_HAPPY1		0x2c0
 #define BTN_TRIGGER_HAPPY2		0x2c1