[PATCH] Add keycode for microphone mute key

[Jerone Young <jerone.young@gmail.com>]

Lenovo is now including a key for muting the microphone on all Thinkpad
models & peripheral keyboards. Currently there is no way to deal with
this key being handled in a common fashion under Linux. This patch
defines a key code for microphone mute so that this key can be mapped
for Thinkpad models & peripheral keyboards.

By having a set keycode this key can be remapped to the common keycode
and userspace can then listen and take some action once the key is
pressed. A common action would be to mute the microphone mixer. 

Thinkpad keyboard pic: http://bit.ly/hLxXL1
Thinkpad usb keyboard pic: http://bit.ly/gfNaQz

Signed-off-by: Jerone Young <jerone.young@gmail.com>

diff --git a/include/linux/input.h b/include/linux/input.h
index 771d6d8..4d8a8ae 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -673,6 +673,8 @@ struct input_keymap_entry {
 #define KEY_CAMERA_LEFT		0x219
 #define KEY_CAMERA_RIGHT	0x21a
 
+#define KEY_MICROPHONE_MUTE	0x21b	/* microphone mute key */
+
 #define BTN_TRIGGER_HAPPY		0x2c0
 #define BTN_TRIGGER_HAPPY1		0x2c0
 #define BTN_TRIGGER_HAPPY2		0x2c1