common/fmap: Update doc link
The old link just redirects to source code on github, which is not the
source that we build fmap from.
BRANCH=none
TEST=make buildall -j
#include "util.h"
#include "version.h"
-/* FMAP structs. See http://code.google.com/p/flashmap/wiki/FmapSpec */
+/*
+ * FMAP structs.
+ * See https://chromium.googlesource.com/chromiumos/third_party/flashmap/+/master/lib/fmap.h
+ */
#define FMAP_NAMELEN 32
#define FMAP_SIGNATURE "__FMAP__"
#define FMAP_SIGNATURE_SIZE 8
