libstagefright: Fix crash during 3D Video playback

The crash was observed while handling extra data in FTB.
This was due to improper assignment of buffer handle to
pBuffer. This assignement is corrected in OMX component
and hence CHECK_EQ for buffer handle in OMX nodeInstance
is removed.

Change-Id: Ib1eb206a201f2e23aec2137b64b93bcb0fc2d221
CRs-Fixed: 328535