MIPS: AR7, BCM63xx: fix gpio_to_irq() return value

The return value of gpio_to_irq() is not a pointer but an integer.

Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/1280/


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