msm: vidc: Don't erase buffer flags in EBD

The flags passed in qbuf need to be preserved when dqbuf is called.  The
flags need to be preserved since the client who queued the buffer might
want to check the buffer characteristics on dqbuf.

CRs-Fixed: 637882
Change-Id: I8afed98dabfefc6694cd12da786480836fc7464e
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>