msm: camera: smmu: Fix unbalanced mutex unlock in camera smmmu

When smmu get handle is called, mutex unlock is called on a lock
that was not acquired. Add mutex lock condition to balance it.
Also, re-organize the conditions for handle types to be mutually
exclusive.

CRs-Fixed: 2584631
Change-Id: I057b8812c8f76e157503eb5c76aa1de174563f3a
Signed-off-by: Mukund Madhusudan Atre <matre@codeaurora.org>