Camera App: return after synchronized block

For some boundary condition when surface allocated is null, due to
return within synchronization block it is giving ANR. This change
will ensure that return take place outside synchronization block.
It will also ensure to notify an object if already in wait state
before invoking wait on it.

CRs-Fixed: 529666
Change-Id: I8532aa410840785923388a879701be9e98b0154f