modules/coreboot: Only check version if we're building coreboot (fixes #841)

Signed-off-by: Nathan Rennie-Waldock <nathan.renniewaldock@gmail.com>

Author: NHellFire

modules/coreboot

@@ -1,5 +1,6 @@
 modules-$(CONFIG_COREBOOT) += coreboot
 
+ifeq "$(CONFIG_COREBOOT)" "y"
 ifeq "$(CONFIG_COREBOOT_VERSION)" "4.8.1"
 	coreboot_version := 4.8.1
 	coreboot_hash := f0ddf4db0628c1fe1e8348c40084d9cbeb5771400c963fd419cda3995b69ad23
@@ -12,6 +13,7 @@ else ifeq "$(CONFIG_COREBOOT_VERSION)" "4.12"
 else
 	$(error "$(BOARD): does not specify coreboot version under CONFIG_COREBOOT_VERSION")
 endif 
+endif
 
 #coreboot_version := git
 #coreboot_repo := https://github.com/osresearch/coreboot