hw/apci: handle 64-bit MMIO regions correctly

In build_crs(), the calculation and merging of the ranges already happens
in 64-bit, but the entry boundaries are silently truncated to 32-bit in the
call to aml_dword_memory(). Fix it by handling the 64-bit MMIO ranges separately.
This fixes 64-bit BARs behind PXBs.

Reported-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>