msm: camera: Fix crash in ispif release

There is a BUG_ON in ispif release function for
ispif base address. but in case of just open and close
of ispif subdevice leads to ispif base NULL.

BUG_ON is removed and proper error is added in ispif
release function to fix the issue.

Change-Id: I0cc12d52aff9db0d9bb8844473f9bd6547270e27
CRs-Fixed: 642603
Signed-off-by: Suresh Vankadara <svankada@codeaurora.org>