ENGR00237682-2: mxc_v4l2_capture: ov5640: support all subsampling modes

ENGR00237682-2: mxc_v4l2_capture: ov5640: support all subsampling modes

Supported the following modes, verified image quality and frame rate
- VGA 30/15fps
- QVGA 30/15fps
- NTSC 30/15fps
- PAL 30/15fps
- 720P 30/15fps
Note: use the same setting as app note of ov5640 dvp
- QCIF 30/15fps
- XGA 22.5/15fps
Note: cannot make XGA work on 30fps. Just a reference of ov5640 datasheet:
1280*960 YUV422 maximum at 22.5fps.
1280*720 YUV422 maximum at 30fps.
Need to confirm later.

Signed-off-by: Sheng Nan <b38800@freescale.com>