ARM: shmobile: r8a7740: Remove SCIF function GPIOs

Those GPIOs have been deprecated by the pinctrl API. They are unused and
unneeded, remove them.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>