MIPS: Cleanup switches with cases that can be merged

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
To: linux-mips@linux-mips.org
To: Andrew Morton <akpm@linux-foundation.org>
To: LKML <linux-kernel@vger.kernel.org>
Patchwork: http://patchwork.linux-mips.org/patch/860/


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