pinctrl/nomadik: add device tree support

This implements pin multiplexing and pin configuration for
the Nomadik pin controller using the device tree.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@stericsson.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Philippe Langlais <philippe.langlais@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>