x86/pci: remove rounding quirk from e820_setup_gap()

Now that the e820 code explicitly reserves 'potentially dangerous'
free physical memory address space to protect ACPI stolen RAM,
there's no need for the rounding quirk in the PCI allocator anymore.

Also, this quirk was open-ended iteration that could end up reserving
a lot of free space and potentially breaking drivers - such as the one
reported by Yannick Roehlly <yannick.roehlly@free.fr> where there's
a PCI device with a large memory resource.

So remove it.

[ Impact: make more of the PCI hole available for assigning pci devices ]

Reported-by: Yannick Roehlly <yannick.roehlly@free.fr>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A01A7C8.5090701@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>