soc/intel/braswell: add vmx support via CPU_INTEL_COMMON

Braswell allready supported vmx, but offered no mechanism to unset it, nor
to set the lock bit required for Windows to recognize virtualization.
Enable this functionality by adding CPU_INTEL_COMMON config.

Test: build/boot Windows 10 on Braswell ChromeOS device, verify Windows shows
virtualization as enabled.

Change-Id: I0d39abaeb9eebcceb37dc791df6b06e521fe1992
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/29570
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/soc/intel/braswell/Kconfig b/src/soc/intel/braswell/Kconfig
index 2ba7992..50c2802 100644
--- a/src/soc/intel/braswell/Kconfig
+++ b/src/soc/intel/braswell/Kconfig
@@ -47,6 +47,7 @@
 	select GENERIC_GPIO_LIB
 	select INTEL_GMA_ACPI
 	select INTEL_GMA_SWSMISCI
+	select CPU_INTEL_COMMON
 
 config VBOOT
 	select VBOOT_STARTS_IN_ROMSTAGE