staging: octeon-usb: move driver out of staging

The Octeon usb driver has been in staging for a long time and used in
Ubiquiti routers for a while now.
It's been built and then tested on real hardware with several usb devices
and it is proven to be stable and ready to be moved to its proper place
in the kernel tree.

Move it to drivers/usb/host and adjust its Makefile, Kconfig and defconfig
dependencies.

Many thanks to the developers who made it happen.

Signed-off-by: Artur Bujdoso <artur.bujdoso@gmail.com>
Link: https://lore.kernel.org/r/Yo0HBIlSXOBM+//9@crux
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>