mb/google/guybrush/var/dewatt: Override SPI fast speed

After assessing the signal integrity, 100 MHz SPI fast speed can be
enabled for SPI ROM.

BUG=b:213403891
TEST=Build and boot to OS in Dewatt board version 2.

Signed-off-by: Kenneth Chan <kenneth.chan@quanta.corp-partner.google.com>
Change-Id: I7301d873e36bec4ee46c9d18293f924500ea9aba
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63685
Reviewed-by: Rob Barnes <robbarnes@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/guybrush/Kconfig b/src/mainboard/google/guybrush/Kconfig
index b2cba6e..069da6c 100644
--- a/src/mainboard/google/guybrush/Kconfig
+++ b/src/mainboard/google/guybrush/Kconfig
@@ -140,7 +140,7 @@
 config OVERRIDE_EFS_SPI_SPEED_MIN_BOARD
 	hex
 	default 0x4 if BOARD_GOOGLE_GUYBRUSH
-	default 0x2 if BOARD_GOOGLE_NIPPERKIN
+	default 0x2 if BOARD_GOOGLE_NIPPERKIN || BOARD_GOOGLE_DEWATT
 	default 0xffffffff
 	help
 	  Minimum board version starting which the Override EFS SPI Speed