[POWERPC] FSL: Add support for PCI-X controllers

Some set of 85xx platforms have PCI-X controllers.  The old arch/ppc
code setup these controllers and we haven't moved it over to arch/powerpc.

We use the PCI-X Capabilties to know if we are in PCI-X mode instead
of the Global Utilities PORDEVSR.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>