[COMMON] g2d: support constraints of MFC

[COMMON] g2d: support constraints of MFC

MFC has the following constraints for buffer access:
- Stride (for both of Luman and Chroma including 2-bit planes)
  - width stride: 16 bytes
  - height alignment: 16 pixels
- Padding:
  - Dummy 256 bytes should be padded between the end of luma and the
    beginning of chroma
  - Dummy 64 bytes(256/4) should be padded between the end of the
    8-bit data and the beginning of the 2-bit data for both of luma
    and chroma.

G2D driver checks and applies the above constraints if
G2D_LAYERFLAG_MFC_STRIDE is set to layer->flags and the format is
YCbCr420 semi-planar. If the format is 8+2 YCbCr420 semi-planar and
the number of buffers is two, the above constraints are applied even
though G2D_LAYERFLAG_MFC_STRIDE is not set.

Change-Id: I3071a7949cf96ac2e80f4845cc1bd189eec51ba6
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>