mb/google/myst: Disable keyboard reset pin

The keyboard reset is not being used on this board, so disable the
functionality.

BUG=b:277294460
TEST=None

Change-Id: If7fb9ab0c9b1260d342313badb65c55bb9f788c0
Signed-off-by: Jon Murphy <jpmurphy@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74285
Reviewed-by: Tim Van Patten <timvp@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/myst/Kconfig

@@ -9,6 +9,7 @@ config BOARD_SPECIFIC_OPTIONS
 	def_bool y
 	select AMD_SOC_CONSOLE_UART
 	select BOARD_ROMSIZE_KB_16384
+	select DISABLE_KEYBOARD_RESET_PIN
 	select DRIVERS_I2C_GENERIC
 	select DRIVERS_I2C_HID
 	select EC_GOOGLE_CHROMEEC