cpu/intel/microcode: Support update before CAR entry

Change-Id: Ie3c2d2e1bc79dcaffd9901e17f83ceeaabd1d659
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/30682
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/cpu/intel/microcode/Kconfig

@@ -0,0 +1,7 @@
+config MICROCODE_UPDATE_PRE_RAM
+	bool
+	depends on SUPPORT_CPU_UCODE_IN_CBFS
+	default y if C_ENVIRONMENT_BOOTBLOCK
+	help
+	  Select this option if you want to update the microcode
+	  during the cache as ram setup.