pci: increase alignment to make more space for hidden code

As reported in

	http://bugzilla.kernel.org/show_bug.cgi?id=13940

on some system when acpi are enabled, acpi clears some BAR for some
devices without reason, and kernel will need to allocate devices for
them.  It then apparently hits some undocumented resource conflict,
resulting in non-working devices.

Try to increase alignment to get more safe range for unassigned devices.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>