When enabling pci reallocation for a pci bridge, we clear the small size
in in bridge and re-assign with requested + optional size for first
several tries, but Ram mention could have problem with one case:
	https://bugzilla.kernel.org/show_bug.cgi?id=15960

After checking the booting log in
	https://lkml.org/lkml/2010/4/19/44
	[regression, bisected] Xonar DX invalid PCI I/O range since 977d17bb



We should not stop too early for io ports.
	Apr 19 10:19:38 [kernel] pci 0000:04:00.0: BAR 7: can't assign io (size 0x4000)
	Apr 19 10:19:38 [kernel] pci 0000:05:01.0: BAR 8: assigned [mem 0x80400000-0x805fffff]
	Apr 19 10:19:38 [kernel] pci 0000:05:01.0: BAR 7: can't assign io (size 0x2000)
	Apr 19 10:19:38 [kernel] pci 0000:05:02.0: BAR 7: can't assign io (size 0x1000)
	Apr 19 10:19:38 [kernel] pci 0000:05:03.0: BAR 7: can't assign io (size 0x1000)
	Apr 19 10:19:38 [kernel] pci 0000:08:00.0: BAR 7: can't assign io (size 0x1000)
	Apr 19 10:19:38 [kernel] pci 0000:09:04.0: BAR 0: can't assign io (size 0x100)
and clear 00:1c.0 to retry again.

This patch removes IORESOUCE_IO checking, and tries one more time.  It
gives us a chance to get an allocation for the 00:1c.0 io port range
because the range from 0x4000 to 0x8000 will be freed and we can use it.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>