PCI: fix 64-vbit prefetchable memory resource BARs

Since patch 6ac665c6 my infiniband
controller hasn't worked.  This is because it has 64-bit prefetchable
memory, which was mistakenly being  taken to be 32-bit memory.  The
resource flags in this case are PCI_BASE_ADDRESS_MEM_TYPE_64 |
PCI_BASE_ADDRESS_MEM_PREFETCH.

This patch checks only for the PCI_BASE_ADDRESS_MEM_TYPE_64 bit; thus
whether the region is prefetchable or not is ignored.  This fixes my
Infiniband.

Reviewed-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>