Fix vboot_reference-firmware linking error

Change-Id: I54052f6d15b9afa52944bf04e09924a3ddb8922e

BUG=none
TEST=emerge-arm-generic vboot_reference-firmware && emerge-arm-generic chromeos-u-boot-next (running)

Review URL: http://codereview.chromium.org/6792031
diff --git a/firmware/arch/arm/include/biosincludes.h b/firmware/arch/arm/include/biosincludes.h
index 2c08dee..84778e3 100644
--- a/firmware/arch/arm/include/biosincludes.h
+++ b/firmware/arch/arm/include/biosincludes.h
@@ -19,6 +19,7 @@
 #define NULL ((void*) 0)
 #endif
 
+#define UINT32_C(x) ((uint32_t) x)
 #define UINT64_C(x) ((uint64_t) x)
 #define PRIu64 "llu"
 extern void debug(const char *format, ...);
diff --git a/firmware/stub/include/biosincludes.h b/firmware/stub/include/biosincludes.h
index bd7e6fd..1e610f8 100644
--- a/firmware/stub/include/biosincludes.h
+++ b/firmware/stub/include/biosincludes.h
@@ -24,6 +24,7 @@
 #define NULL ((void*) 0)
 #endif
 
+#define UINT32_C(x) ((uint32_t)x)
 #define UINT64_C(x) ((uint64_t)x)
 #define __attribute__(x)
 #define PRIu64 "llu"