MIPS: OCTEON: octeon-irq: fix spelling mistake "to" -> "too"

There is a spelling mistake in a dev_err message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org
Cc: linux-kernel@vger.kernel.org