pinctrl: samsung: Remove unused local variable

The local variable drvdata is not used in samsung_gpio_set_direction.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>