[media] s5p-fimc: Fix camera input configuration in subdev operations

When using only subdev user-space operations the camera
interface input was not configured properly. Fix this by
updating the corresponding data structure in set_fmt
operation.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>