Add PCI .shutdown method so that we can disable the device during shutdown or reboot. Without this, the reboot doesn't work well on some platforms. This fixes http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2124 Tested-by: pablo <pablolm2005@gmail.com> Signed-off-by: Zhu Yi <yi.zhu@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>