gpio: samsung: Fix off-by-one bug in gpio addresses

Move gpc4 to the end of the automatically processed gpio controllers so
we don't taint the automatic offset calculation.

This bug caused all controllers coming after gpc4 to map to the
incorrect address. The result is <&gpd1 0 0 0 0> would actually map to
GPIO 0 in gpd0.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Doug Anderson <dianders@chromium.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>