[POWERPC] FSL: Cleanup how we detect if we are a PCIe controller

Use the PCI capabilities to determine if we are PCIe PHB.  Also use
PPC_INDIRECT_TYPE_NO_PCIE_LINK since the Freescale PCIe controllers
will lock the system if they don't have link and you try to do a config
access to anything but the PHB.

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