ASoC: msm: qdsp6v2: move frame info to be per session based

When audio stream manager returns READ_DONE event, the payload
which comes with the event contains size of captured audio data
and offset indicating where the data starts in the buffer.
Before this change, size and offset information is stored in
global variable which can be shared by all capture sessions.
If the offset is overwritten by another session with larger value,
buffer can be indexed beyond actual size of buffer when copying
captured data into user-space buffer. Move the structure as part
of per session private data to prevent overwriting.

Change-Id: Iaee12b0153b945a315e95c862fa2522cbd69c6f8
Signed-off-by: Patrick Lai <plai@codeaurora.org>
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>