MIPS: MT: Fix typo

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13323/


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