[pci] Ignore pre-set 64-bit BARs on 32-bit platforms

Currently, Linux always rejects a device which has a pre-set 64-bit
address on a 32-bit platform.  On systems which do not do PCI
initialization in firmware, this causes some devices which don't
correctly power up with all BARs zero to fail.

This patch makes the kernel automatically zero out such an address
(thus treating it as if it had not been set at all, meaning it will
assign an address if necessary).

I have done this only for devices, not bridges.  It seems potentially
hazardous to do for bridges.
Signed-off-by: H. Peter Anvin <hpa@c2micro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>