ideapad_laptop: Add an event for mic mute hotkey

BugLink: http://bugs.launchpad.net/bugs/1607153

Newer ideapads support a new mic hotkey implemented via an ACPI
interface. This patch converts the mic mute event to a keycode
KEY_MICMUTE.
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Acked-by: Ike Panhc <ike.pan@canonical.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
(cherry picked from commit 48f67d62)
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/platform/x86/ideapad-laptop.c

@@ -563,6 +563,7 @@ static void ideapad_sysfs_exit(struct ideapad_private *priv)
 static const struct key_entry ideapad_keymap[] = {
 	{ KE_KEY, 6,  { KEY_SWITCHVIDEOMODE } },
 	{ KE_KEY, 7,  { KEY_CAMERA } },
+	{ KE_KEY, 8,  { KEY_MICMUTE } },
 	{ KE_KEY, 11, { KEY_F16 } },
 	{ KE_KEY, 13, { KEY_WLAN } },
 	{ KE_KEY, 16, { KEY_PROG1 } },
@@ -805,6 +806,7 @@ static void ideapad_acpi_notify(acpi_handle handle, u32 event, void *data)
 				break;
 			case 13:
 			case 11:
+			case 8:
 			case 7:
 			case 6:
 				ideapad_input_report(priv, vpc_bit);