staging: octeon-usb: eliminate 64-bit register access wrappers

Eliminate 64-bit register access wrappers. Since we don't implement
register-level debugging outputs, these are useless.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>