soc/intel/skylake: pass SataSpeedLimit param to FSP2

The Librem13v2 needs to set this parameter to work around
power-related issues with some SATA devices.

Change-Id: I7fcef36ec8662e18834394b72427a0633c6b7e92
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/22045
Reviewed-by: Youness Alaoui <snifikino@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/skylake/chip.h

@@ -148,6 +148,7 @@ struct soc_intel_skylake_config {
 	u8 SataSalpSupport;
 	u8 SataPortsEnable[8];
 	u8 SataPortsDevSlp[8];
+	u8 SataSpeedLimit;
 
 	/* Audio related */
 	u8 EnableAzalia;