soc/intel/skylake: Move `SataTestMode` to Kconfig

This option is not mainboard-specific, and should be user-visible.

Change-Id: I9ff2ca984cd238a112af4efd7685f142cc6e5459
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52099
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
diff --git a/src/soc/intel/skylake/Kconfig b/src/soc/intel/skylake/Kconfig
index 29f8159..5024ef4 100644
--- a/src/soc/intel/skylake/Kconfig
+++ b/src/soc/intel/skylake/Kconfig
@@ -91,6 +91,12 @@
 	bool "Enable Hyper-Threading"
 	default y
 
+config ENABLE_SATA_TEST_MODE
+	bool "Enable SATA test mode"
+	default n
+	help
+	  Enable SATA test mode in FSP-S.
+
 config CPU_INTEL_NUM_FIT_ENTRIES
 	int
 	default 10