pinctrl/nomadik: adopt pinctrl sleep mode management

This fix makes pinctrl-nomadik able to handle
suspend/resume events and change hogged pins states
accordingly.

Signed-off-by: Julien Delacou <julien.delacou@stericsson.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>