x86, mce: remove oops_begin() use in 64bit machine check

First 32bit doesn't have oops_begin, so it's a barrier of using
this code on 32bit.

On closer examination it turns out oops_begin is not
a good idea in a machine check panic anyways. All oops_begin
does it so check for recursive/parallel oopses and implement the
"wait on oops" heuristic. But there's actually no good reason
to lock machine checks against oopses or prevent them
from recursion. Also "wait on oops" does not really make
sense for a machine check too.

Replace it with a manual bust_spinlocks/console_verbose.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/cpu/mcheck/mce.c

@@ -178,7 +178,8 @@ static void mce_panic(char *msg, struct mce *backup, u64 start)
 {
 	int i;
 
-	oops_begin();
+	bust_spinlocks(1);
+	console_verbose();
 	for (i = 0; i < MCE_LOG_LEN; i++) {
 		u64 tsc = mcelog.entry[i].tsc;