[media] solo6x10: expose encoder quantization setting as V4L2 control

solo6*10 boards have configurable quantization parameter which takes
values from 0 to 31, inclusively.

This change enables setting it with ioctl VIDIOC_S_CTRL with id
V4L2_CID_MPEG_VIDEO_H264_MIN_QP.
Signed-off-by: Andrey Utkin <andrey.utkin@corp.bluecherry.net>
Signed-off-by: Ismael Luceno <ismael.luceno@corp.bluecherry.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/staging/media/solo6x10/solo6x10-v4l2-enc.c

@@ -1121,6 +1121,9 @@ static int solo_s_ctrl(struct v4l2_ctrl *ctrl)
 	case V4L2_CID_MPEG_VIDEO_GOP_SIZE:
 		solo_enc->gop = ctrl->val;
 		return 0;
+	case V4L2_CID_MPEG_VIDEO_H264_MIN_QP:
+		solo_enc->qp = ctrl->val;
+		return 0;
 	case V4L2_CID_DETECT_MD_GLOBAL_THRESHOLD:
 		solo_enc->motion_thresh = ctrl->val << 8;
 		if (!solo_enc->motion_global || !solo_enc->motion_enabled)
@@ -1271,6 +1274,8 @@ static struct solo_enc_dev *solo_enc_alloc(struct solo_dev *solo_dev,
 			V4L2_CID_SHARPNESS, 0, 15, 1, 0);
 	v4l2_ctrl_new_std(hdl, &solo_ctrl_ops,
 			V4L2_CID_MPEG_VIDEO_GOP_SIZE, 1, 255, 1, solo_dev->fps);
+	v4l2_ctrl_new_std(hdl, &solo_ctrl_ops,
+			V4L2_CID_MPEG_VIDEO_H264_MIN_QP, 0, 31, 1, SOLO_DEFAULT_QP);
 	v4l2_ctrl_new_std_menu(hdl, &solo_ctrl_ops,
 			V4L2_CID_DETECT_MD_MODE,
 			V4L2_DETECT_MD_MODE_THRESHOLD_GRID, 0,