msm: vidc: Add encoder input buffers dynamic

Video encoder clients can queue new input buffers anytime.
Hence video driver should handle them as dynamic buffers.

CRs-Fixed: 2023979
Change-Id: I13a6693122207984d290f227ab01186c2e8a4970
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>
Signed-off-by: Karthikeyan Periasamy <kperiasa@codeaurora.org>