[Mediacodec] Fix media codec surface memory leak

I use Amlogic platform. When I increase ION buffer，It can play use mediacodec. But I found the problem of memory leak. when play video it has 6 buffers, but after played it has one buffer not released. Every play video it always has more one buffer not released.  So when I play some times, the log show out of memory.
This patch fixed this problem.
Could probably do with some defines or enums for this instead of magic numbers.