[PATCH] airo: disable the PCI device when unloading module

Fix an assymetry between pci_{enable,disable}_device. airo did not disable
the PCI device when unloading the module. This caused suspend failures
after modprobe -r airo && modprobe airo.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>