* stable/for-linus-3.7:
xen/swiotlb: Fix compile warnings when using plain integer instead of NULL pointer.
xen/swiotlb: Remove functions not needed anymore.
xen/pcifront: Use Xen-SWIOTLB when initting if required.
xen/swiotlb: For early initialization, return zero on success.
xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used.
xen/swiotlb: Move the error strings to its own function.
xen/swiotlb: Move the nr_tbl determination in its own function.
swiotlb: add the late swiotlb initialization function with iotlb memory
xen/swiotlb: With more than 4GB on 64-bit, disable the native SWIOTLB.
xen/swiotlb: Simplify the logic.