Add tests for vboot_reference stateful_util.c

BUG=chromium-os:17564
TEST=make && make runtests

Change-Id: I5d55be2dfead0c5d7af72841cbd6c65485685cd6
Reviewed-on: http://gerrit.chromium.org/gerrit/6596
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>

firmware/lib/stateful_util.c

@@ -9,6 +9,12 @@
 
 #include "utility.h"
 
+void StatefulInit(MemcpyState* state, void* buf, uint64_t len) {
+  state->remaining_buf = buf;
+  state->remaining_len = len;
+  state->overrun = 0;
+}
+
 void* StatefulSkip(MemcpyState* state, uint64_t len) {
   if (state->overrun)
     return NULL;