msm: camera: cpas: Correct error handling in cpas start

cpas driver goes into error handling during any error and
reset the error return code as well. This makes cpas start
to return success though it is failed.

Correct error handling be returning failure to cpas clients.

CRs-Fixed: 2684122
Change-Id: I4cf90de550095bc1884e59ae200c9c89e11d214d
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>