PCI: Add pci_enable_device_{io,mem} intefaces

The pci_enable_device_bars() interface isn't well suited to PCI
because you can't actually enable/disable BARs individually on
a device. So for example, if a device has 2 memory BARs 0 and 1,
and one of them (let's say 1) has not been successfully allocated
by the firmware or the kernel, then enabling memory decoding
shouldn't be permitted for the entire device since it will decode
whatever random address is still in that BAR 1.

So a device must be either fully enabled for IO, for Memory, or
for both. Not on a per-BAR basis.

This provides two new functions, pci_enable_device_io() and
pci_enable_device_mem() to replace pci_enable_device_bars(). The
implementation internally builds a BAR mask in order to be able
to use existing arch infrastructure.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>