mb/google/skyrim: Update SPI settings for skyrim

Update SPI setting as below:

Normal speed:33mhz
Fast speed:66mhz
Alt speed:66mz
TPM speed:33mhz

BUG=b:225213679
TEST=boot skyrim and verify spi settings.

Signed-off-by: Chris.Wang <chris.wang@amd.corp-partner.google.com>
Change-Id: Icbe4b9f4794f7e883c3819258ede809c3c8922b0
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63717
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/mainboard/google/skyrim/Kconfig

@@ -71,4 +71,22 @@ config VBOOT
 	select VBOOT_SEPARATE_VERSTAGE
 	select VBOOT_STARTS_IN_BOOTBLOCK
 
+if !EM100	# EM100 defaults in soc/amd/common/blocks/spi/Kconfig
+config EFS_SPI_READ_MODE
+	default 2          # Dual IO (1-1-2)
+
+config EFS_SPI_SPEED
+	default 0	# 66MHz
+
+config EFS_SPI_MICRON_FLAG
+	default 0
+
+config NORMAL_READ_SPI_SPEED
+	default 1	# 33MHz
+
+config ALT_SPI_SPEED
+	default 0	# 66MHz
+
+endif # !EM100
+
 endif # BOARD_GOOGLE_BASEBOARD_SKYRIM