MIPS: Octeon: Update DMA mapping operations for OCTEON II processors.

OCTEON II has a new dma to phys mapping method for PCIe.  Define
OCTEON_DMA_BAR_TYPE_PCIE2 to denote this case, and handle it.

OCTEON II also needs a swiotlb if the OHCI USB driver is enabled, so
allocate this too.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2983/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>