mm-video-v4l2: vdec: fix decoder output dump issue

Currently when decoder is in dynamic buffer mode,
output buffers are not mapped and dump feature can't work.
Add mmap/munmap in dump function to fix it.

Change-Id: I7d43f2e189b3ef17e50f40394a1752a7557c0be8
CRs-Fixed: 2140045
1 file changed