MIPS: Netlogic: USB support for XLP

MIPS: Netlogic: USB support for XLP

The XLP USB controller appears as a device on the internal SoC PCIe
bus, the block has 2 EHCI blocks and 4 OHCI blocks. Change are to:

* Add files netlogic/xlp/usb-init.c and asm/netlogic/xlp-hal/usb.h
  to initialize the USB controller and define PCI fixups. The PCI
  fixups are to setup interrupts and DMA mask.
* Update include/asm/xlp-hal/{iomap.h,pic.h,xlp.h} to add interrupt
  mapping for EHCI/OHCI interrupts.

Signed-off-by: Ganesan Ramalingam <ganesanr@netlogicmicro.com>
Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3756/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>