PCI: Don't try to disable Bus Master on disconnected PCI devices
PCI: Don't try to disable Bus Master on disconnected PCI devices

This is a fix for commit 7897e60227 ("PCI: Disable Bus Master
unconditionally in pci_device_shutdown()").  Vivek reported that
with this commit, kexec failed because none of his SATA disks
came up.

A ->shutdown() callback might put the device in D3cold, which means config
space is no longer available.

[bhelgaas: changelog]
Link: https://lkml.org/lkml/2013/3/12/529
Reported-and-Tested-by: Vivek Goyal <61d11262d0d9873ddb5a887f48fcb04e8c5973d0@redhat.com>
Signed-off-by: Konstantin Khlebnikov <3b96b99f19643d33e1bfa1caa535c041c3608549@openvz.org>
Signed-off-by: Bjorn Helgaas <f10ec01be0c6b54271af5c550cd257810bdf3268@google.com>
Cc: Rafael J. Wysocki <27ffc44a8ec6a212fba98cfc3246c6ce8ab131e0@intel.com>
TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs