soc/intel/skylake: Add option to toggle Hyper-Threading

Tested on Supermicro X11SSH-TF.

Change-Id: I3ebab68ff868c78105bb4b35abffb92f3ccf1705
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35208
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/intel/skylake/Kconfig

@@ -78,6 +78,11 @@ config CPU_SPECIFIC_OPTIONS
 	select TSC_SYNC_MFENCE
 	select UDELAY_TSC
 
+config FSP_HYPERTHREADING
+	bool "Enable Hyper-Threading"
+	depends on MAINBOARD_USES_FSP2_0
+	default y
+
 config CPU_INTEL_NUM_FIT_ENTRIES
 	int
 	default 10

src/soc/intel/skylake/romstage/romstage_fsp20.c

@@ -252,6 +252,7 @@ static void soc_memory_init_params(FSP_M_CONFIG *m_cfg,
 		m_cfg->PchHpetDeviceNumber = V_P2SB_HBDF_DEV;
 		m_cfg->PchHpetFunctionNumber = V_P2SB_HBDF_FUN;
 	}
+	m_cfg->HyperThreading = CONFIG(FSP_HYPERTHREADING);
 }
 
 static void soc_primary_gfx_config_params(FSP_M_CONFIG *m_cfg,