sh-pfc: r8a7779: Remove GPIO data

GPIOs are now handled by a separate driver, remove GPIO data from the
SoC information structure.

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