ipw2100: fix rebooting hang with driver loaded

ipw2100: fix rebooting hang with driver loaded

commit 52ce3e9a7db754b78cf2cbabc87013f921b25b28 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>