[PATCH] PCI: 'is_enabled' flag should be set/cleared when the device is actually enabled/disabled

I think 'is_enabled' flag in pci_dev structure should be set/cleared
when the device actually enabled/disabled. Especially about
pci_enable_device(), it can be failed. By this change, we will also
get the possibility of refering 'is_enabled' flag from the functions
called through pci_enable_device()/pci_disable_device().

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>