mb/google/fatcat/var/kinmen: Add Fn key scancode

The Fn key on kinmen emits a scancode of 94 (0x5e).

BUG=b:409148565
TEST=Flash kinmen, boot to Linux kernel, and verify that KEY_FN is
generated when pressed using `evtest`

Change-Id: If919c6f421719e06399620b17e1f4f5a161a7de2
Signed-off-by: Ivy Jian <ivy.jian@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88207
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/fatcat/Kconfig

@@ -112,6 +112,7 @@ config BOARD_GOOGLE_FRANCKA
 config BOARD_GOOGLE_KINMEN
 	select BOARD_GOOGLE_BASEBOARD_FATCAT
 	select HAVE_SLP_S0_GATE
+	select MAINBOARD_HAS_GOOGLE_STRAUSS_KEYBOARD
 
 if BOARD_GOOGLE_FATCAT_COMMON