ARM: dts: cros-ec-keyboard: Add LOCK key to keyboard matrix

The LOCK key is at KSO9/KSI3 for Chromebook Flip and other devices
that use the Chrome OS EC keyboard matrix.
Signed-off-by: James Chao <james_chao@asus.com>
Signed-off-by: YH Huang <yh.huang@mediatek.com>
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/cros-ec-keyboard.dtsi

@@ -55,6 +55,7 @@ MATRIX_KEY(0x03, 0x03, KEY_5)
 			MATRIX_KEY(0x03, 0x04, KEY_F5)
 			MATRIX_KEY(0x03, 0x06, KEY_6)
 			MATRIX_KEY(0x03, 0x08, KEY_MINUS)
+			MATRIX_KEY(0x03, 0x09, KEY_F13)
 			MATRIX_KEY(0x03, 0x0b, KEY_BACKSLASH)
 			MATRIX_KEY(0x03, 0x0c, KEY_MUHENKAN)