msm: camera: isp: Correct error check in clock rate assignment

Error check is not proper while assigning clock rates.
this is causing failure on updated clock rates.

CRs-Fixed: 2998722
Change-Id: Id8634438a7930362e4b8eb010b523dc2def1f043
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>