ARM: 6102/1: nomadik-gpio: set a default trigger for interrupts

Set a default trigger type for interrupts, otherwise if request_irq is
called without specifiying a trigger type, the interrupt will not
actually be enabled.

Acked-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>