MIPS: Netlogic: Warn on invalid irq

Warn and return if invalid IRQ is passed to nlm_set_pic_extra_ack.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6862/


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