media: solo6x10: remove unneeded GPIO direction setters

GPIO core already handles missing direction_input/output() callbacks.
The ones in this driver also effectively return magic numbers which is
not optimal either (the number accidentally corresponds with -EPERM which
is different from the number GPIOLIB returns and so inconsistent). Just
remove them.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>