arch/x86/acpi: Add code for KEY_MENU

Support of MENU key (aka hamburger) for Chromebooks with Vivaldi
keyboard

BUG=b:215038215
TEST=manually tested on Anahera device: pressing T13 key opens menu

Signed-off-by: Boris Mittelberg <bmbm@google.com>
Change-Id: I07873dd9385c743a6512408688ec44a5e97219f9
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61835
Reviewed-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Lance Zhao
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/include/acpi/acpigen_ps2_keybd.h b/src/include/acpi/acpigen_ps2_keybd.h
index e32ca2a..7dd8282 100644
--- a/src/include/acpi/acpigen_ps2_keybd.h
+++ b/src/include/acpi/acpigen_ps2_keybd.h
@@ -26,6 +26,7 @@
 	PS2_KEY_PREV_TRACK,
 	PS2_KEY_KBD_BKLIGHT_TOGGLE,
 	PS2_KEY_MICMUTE,
+	PS2_KEY_MENU,
 };
 
 #define PS2_MIN_TOP_ROW_KEYS		10