fwlib: Map architecture armv7 to arm

In coreboot the architecture for our ARM platforms
is armv7. In order to have vboot_reference pick up the
right build parameters, map armv7 to arm.

BUG=none
BRANCH=none
TEST=lots more changes on coreboot needed for a reasonable
     test. Right now coreboot compiles fine with ramstage
     verification and this patch.

Change-Id: I64dad9be663b7bd7d80d138b3c49ae8f4699f01d
Reviewed-on: https://chromium-review.googlesource.com/170071
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Stefan Reinauer <reinauer@google.com>
Tested-by: Stefan Reinauer <reinauer@google.com>
diff --git a/Makefile b/Makefile
index b810a5f..d4b6245 100644
--- a/Makefile
+++ b/Makefile
@@ -99,6 +99,8 @@
   override FIRMWARE_ARCH := x86
 else ifeq (${FIRMWARE_ARCH},amd64)
   override FIRMWARE_ARCH := x86_64
+else ifeq (${FIRMWARE_ARCH},armv7)
+  override FIRMWARE_ARCH := arm
 endif
 
 # Provide default CC and CFLAGS for firmware builds; if you have any -D flags,