OMXVideoDecoderBase: change MapRawNV12 to CopyRawFrameData

other surface formats (422H for mjpeg) is supported besides NV12
it does real copy instead memory map
OMXVideoDecoderBase: fix wild pointer bug.

mDisplayXPtr is not initialized in OMXVideoDecoderBase constructor
so it is a wild pointer before initialized later.

Signed-off-by: Zhong Cong <congx.zhong@intel.com>