spi: omap-100k: Drop include

The OMAP-100k driver includes <linux/gpio.h> but does not
use any symbols from it, so drop the include.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200714073357.34879-1-linus.walleij@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>