gpio: samsung: Remove OF support for s3c24xx

There is no users of this code and there is already a pinctrl
driver written for s3c24xx which is going to be used on any
s3c24xx DT platforms. Hence this has been effectively a dead
code in mainline.

This reverts commit 172c6a13653ac8cd6a231293b87c93821e90c1d6
gpio: samsung: add devicetree init for s3c24xx arches

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>