usb: OHCI/EHCI support for Netlogic XLS processor.

Add supprt for on-chip USB controller for Netlogic XLS MIPS64
SoC processor family.
Changes are:
 - update ehci-hcd.c and ohci-hcd.c to add XLS hcds
 - add ehci-xls.c: EHCI support for Netlogic XLS.
 - add ohci-xls.c: OHCI support for Netlogic XLS.

Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>