sh-pfc: Return an error if a pin doesn't support the requested direction

When setting a pin direction verify that the requested direction is
supported, and return an error if it isn't.

This requires pin configuration information to be supplied by SoC data.
The check is a no-op if the information is not supplied.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>