ASoC: msm-cpe-lsm: Buffer allocation cleanup

The buffer used for look ahead buffering is allocated by cpe core
driver. Fix to perform cleanup of data structures shared across platform
driver and cpe core to allow buffer allocation to be done by platform
driver.

Change-Id: Ifaff24025292f2e5be6572ca50dcc281ed8d4f84
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>