ARM: at91: add gpio suspend/resume support when using pinctrl

gpio suspend/resume and wakeup sources where not managed when using pinctrl so
it was impossible to wake up the system with a gpio.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>