This patch fixes a problem introduced when CK804 support was added.  mmio_base can only be set in the CK804 case,
else libata will attempt to iounmap mmio_base, which isn't iomapped for the non-CK804 case.  Still need the bar 5
address, so steal from host_set->ports[0]->ioaddr.scr_addr.  Jeff, let me know if this is a bad thing to do.