MIPS: Replace calls to obsolete strict_strto call with kstrto* equivalents.

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: richard@nod.at
Cc: akpm@linux-foundation.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>