Enabled paired extBuffers support in ExtBufHolder
Enabled paired extBuffers support in ExtBufHolder

ExtBufHolder::AddExtBuffer now can allocate two
extBuffers in a raw. Return pointer is always the first buffer.
Access to the 2nd extBuffer is via GetExtBuffer(1).

Signed-off-by: Dmitry Ermilov <b906d09bf4e9d5ffa97d91f4baa9152f6d31529a@intel.com>

Intel-Media-SDK/MediaSDK,Intel-Media-SDK/MediaSDK,Intel-Media-SDK/MediaSDK,Intel-Media-SDK/MediaSDK,Intel-Media-SDK/MediaSDK