msm: vidc: make realtime as default

By default, a session is realtime. Client can
overwrite as non-realtime.Fixed realtime value
for decoder.Deprecated VIDC_REALTIME flag usage.

Change-Id: I5a1d1c9bdab18d3dfb73f3b21a23054de07d77a1
Signed-off-by: Darshana Patil <darshana@codeaurora.org>