V4L/DVB: uvcvideo: Clamp control values to the minimum and maximum values

When setting a control, the V4L2 specification requires drivers to
either clamp the control value to the [minimum, maximum] range or return
the -ERANGE error.

Fix the driver to clamp control values to the valid range in
uvc_ctrl_set() and make sure the value differs from the minimum by an
integer multiple of step.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/uvc/uvc_v4l2.c b/drivers/media/video/uvc/uvc_v4l2.c
index 23239a4..bf1fc7f 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -549,6 +549,8 @@
 			return ret;
 		}
 		ret = uvc_ctrl_commit(chain);
+		if (ret == 0)
+			ctrl->value = xctrl.value;
 		break;
 	}