b43: Fix suspend/resume

This fixes suspend/resume.

We must not overwrite the MAC addresses on resume. Otherwise
the card won't ACK any packets anymore.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>