ARM: shmobile: Select PINCTRL

The pin control framework is required by mach-shmobile. Select it in
Kconfig.

This will be required when the sh-pfc driver will move to
drivers/pinctrl/.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>