[PATCH] x86_64: increase MCE bank counts

There is one CPU here whose MCE bank count is 6. This patch increases
x86_64's MCE bank count.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>