arc: select GPIOLIB directly

Instead of indirectly selecting GPIOLIB via the
ARCH_REQUIRE_GPIOLIB symbol, just select GPIOLIB.

Cc: Michael Büsch <m@bues.ch>
Cc: linux-snps-arc@lists.infradead.org
Acked-by: Vineet Gupta <vgupt@synopsys.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>