platform/x86: asus-nb-wmi: Support left round button on N56VB

The N56VB laptop has a round button located on the left side above the
keyboard. Map it to F13 since it does not have any predeterminated
purpose.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/asus-nb-wmi.c

@@ -471,6 +471,7 @@ static const struct key_entry asus_nb_wmi_keymap[] = {
 	{ KE_KEY, 0x67, { KEY_SWITCHVIDEOMODE } }, /* SDSP LCD + CRT + TV */
 	{ KE_KEY, 0x6B, { KEY_TOUCHPAD_TOGGLE } },
 	{ KE_IGNORE, 0x6E, },  /* Low Battery notification */
+	{ KE_KEY, 0x71, { KEY_F13 } }, /* General-purpose button */
 	{ KE_KEY, 0x7a, { KEY_ALS_TOGGLE } }, /* Ambient Light Sensor Toggle */
 	{ KE_KEY, 0x7c, { KEY_MICMUTE } },
 	{ KE_KEY, 0x7D, { KEY_BLUETOOTH } }, /* Bluetooth Enable */