amd64_edac: Mark amd64_decode_bus_error as static

This patch marks the function amd64_decode_bus_error() as static because
it is not used outside of amd64_edac.c.

It also eliminates the following warning:
drivers/edac/amd64_edac.c:2038:6: warning: no previous prototype for ‘amd64_decode_bus_error’ [-Wmissing-prototypes]
Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Link: http://lkml.kernel.org/r/7cddbd4c69ed493f183383e98853181aaf75b26b.1387029387.git.rashika.kheria@gmail.comSigned-off-by: NBorislav Petkov <bp@suse.de>

drivers/edac/amd64_edac.c

@@ -2035,7 +2035,7 @@ static inline void __amd64_decode_bus_error(struct mem_ctl_info *mci,
 	__log_bus_error(mci, &err, ecc_type);
 }
 
-void amd64_decode_bus_error(int node_id, struct mce *m)
+static void amd64_decode_bus_error(int node_id, struct mce *m)
 {
 	__amd64_decode_bus_error(mcis[node_id], m);
 }