Extend Demux user-space API to set decoder buffers allocated externally by user, supporting multiple linear buffers or a single cyclic buffer. Internal decoder buffer allocation is still supported. Change-Id: I1df53d3961ab7934bd4a969cff1dae435ae1dfc6 Signed-off-by: Gilad Broner <gbroner@codeaurora.org> Signed-off-by: Neha Pandey <nehap@codeaurora.org>