x86, mce: fix confusion between bank attributes and mce attributes

Commit cebe182033f156b430952370fb0f9dbe6e89b081 had an unnecessary,
wrong change: &mce_banks[i].attr is equivalent to the former
bank_attrs[i], not to mce_attrs[i].

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <4B1E05CC.4040703@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>