MIPS: IP22/IP28: Fix typo

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: adam.buchbinder@gmail.com
Cc: trivial@kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13328/


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