mb/google/dedede/var/awasuki: Add Fn key scancode

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

BUG=b:355538142
TEST=Flash awasuki, boot to Linux kernel, and verify that KEY_FN is
generated when pressed using `evtest`.

Change-Id: Ic7aa183bf314fed4901133dc70d848d84fab0784
Signed-off-by: Weimin Wu <wuweimin@huaqin.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83724
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: zhongtian wu <wuzhongtian@huaqin.corp-partner.google.com>
Reviewed-by: Eric Lai <ericllai@google.com>

src/mainboard/google/dedede/Kconfig

@@ -1,5 +1,8 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
+config ACPI_FNKEY_GEN_SCANCODE
+	default 94 if BOARD_GOOGLE_AWASUKI
+
 config BOARD_GOOGLE_BASEBOARD_DEDEDE
 	def_bool n
 	select BOARD_ROMSIZE_KB_16384 if !BOARD_ROMSIZE_KB_32768