media: v4l2-ioctl: S_CTRL output the right value

If the driver does not implement s_ctrl, but it does implement
s_ext_ctrls, we convert the call.

When that happens we have also to convert back the response from
s_ext_ctrls.

Fixes v4l2_compliance:
Control ioctls (Input 0):
		fail: v4l2-test-controls.cpp(411): returned control value out of range
		fail: v4l2-test-controls.cpp(507): invalid control 00980900
	test VIDIOC_G/S_CTRL: FAIL

Fixes: 35ea11ff ("V4L/DVB (8430): videodev: move some functions from v4l2-dev.h to v4l2-common.h or v4l2-ioctl.h")
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>