msm: cpp: Do not free stripe info pointer allocated by backend

Strip info pointer is allocated by backend and should be deallocated
by backend code. Also providing a invalid pointer results in a crash
during error scenarios.

Change-Id: Ic58690cdd16ae91c268e7fe36cad3ec7c1000ce4
Signed-off-by: Krishnankutty Kolathappilly <kkolatha@codeaurora.org>