libertas: Prepare stuff for if_spi.c pm support

To support suspend/resume in if_spi we need two things:
- re-setup fw in lbs_resume(), because if_spi powercycles card;
- don't touch hwaddr on second lbs_update_hw_spec() call for same
  reason;

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>