audio-ar: Initialize gaplessMeta with 0 based on encoder delay.

As we are not initializing gaplessMetadata, Sometimes this value
was getting assigned with improper encoder delay which was causing
offload playback failure.To avoid this initialize gaplessMeta with
0 if setparam for encoder delay or encoder padding was not called

Change-Id: Ib9894903a8f4f0441710cc34446b38e115792916