msm: vidc: add debugfs support for dynamic buffer mode

video driver debugfs will provide the following info
(a) buffer mode for each buffer type
(b) list of pending output dynamic buffers with
firmware and driver along with their ref count, fd
and address.

Change-Id: Idc3816c825dfb0c174e6d01b72e741d14f9299e3
Signed-off-by: Arun Menon <avmenon@codeaurora.org>