msm-camera: Assign NULL after freeing memory

In msm_actuator we need to assign memory
pointer to  NULL after freeing that memory
using kfree.

CRs-Fixed: 621818
Change-Id: Id6bc85a74c94556b53f4a868a168637e0733bde4
Signed-off-by: Raghu DP <dp.raghu@codeaurora.org>
Merge "msm-camera: Assign NULL after freeing memory" into du44