media: cec: seco: Drop pointless include

This driver uses GPIO descriptors not the old legacy GPIO
API so stop including <linux/gpio.h>.

Fix a bug using a completely unrelated legacy API flag
GPIOF_IN by switching to the actually desired flag
GPIOD_IN.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>