mb/google/brox/jubilant: Add Fn key scancode

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

BUG=b:324079605
TEST=Flash jubilant, boot to Linux kernel, and verify that KEY_FN is
generated when pressed using `evtest`.

Change-Id: I963b0aa85598097fea69ec34d1e79ec0bbec3db3
Signed-off-by: Morris Hsu <morris-hsu@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83821
Reviewed-by: Ren Kuo <ren.kuo@quanta.corp-partner.google.com>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/brox/Kconfig

@@ -1,7 +1,7 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
 config ACPI_FNKEY_GEN_SCANCODE
-	default 94 if BOARD_GOOGLE_LOTSO
+	default 94 if (BOARD_GOOGLE_LOTSO || BOARD_GOOGLE_JUBILANT)
 
 config BOARD_GOOGLE_BROX_COMMON
 	def_bool n