PCI: Handle IORESOURCE_PCI_FIXED when sizing resources

The new Enhanced Allocation (EA) capability support (patches to follow)
creates resources with the IORESOURCE_PCI_FIXED set.  Since these resources
cannot be relocated or resized, their alignment is not really defined, and
it is therefore not specified.  This causes a problem in pbus_size_mem()
where resources with unspecified alignment are disabled.

So, in pbus_size_mem() skip IORESOURCE_PCI_FIXED resources, instead of
disabling them.

[bhelgaas: folded in "flags & IORESOURCE_PCI_FIXED" fix from David]
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Sean O. Stalley <sean.stalley@intel.com>