msm: camera: Fix memory corrupt in actuator step table

The total steps used to generate the step position table is
passed from userspace and can go out of sync with the region
boundary information in kernel. This can corrupt the memory
and hence add necessary check to ensure the boundary never
exceeds total steps.

CRs-Fixed: 362769
Change-Id: Ia937ba3abda33e49d0d048d894321fb2edf9a0c1
Signed-off-by: Rajakumar Govindaram <rajakuma@codeaurora.org>

Conflicts:
	drivers/media/video/msm/actuators/msm_actuator.c