MIPS: OCTEON: add USB clock type for D-Link DSR-1000N

Add USB clock type for D-Link DSR-1000N.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <ddaney.cavm@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7218/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>