[media] s5p-fimc: Honour sizeimage in VIDIOC_S_FMT

Allow memory buffer size to be increased by means of
struct v4l2_pix_plane_format::sizeimage at VIDIOC_S_FMT ioctl.

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>