MIPS: Cavium: Fix typo

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: david.daney@cavium.com
Cc: janne.huttunen@nokia.com
Cc: aaro.koskinen@nokia.com
Cc: trivial@kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13324/
Patchwork: https://patchwork.linux-mips.org/patch/13325/
Patchwork: https://patchwork.linux-mips.org/patch/13326/
Patchwork: https://patchwork.linux-mips.org/patch/13327/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>