msm: camera: isp: Set the clock rate before ahb vote

Set the vfe clock rate before putting the ahb vote into
suspend otherwise the clock vote will bump up the ahb
vote and prevent shutdown.

CRs-Fixed: 1078215
Change-Id: I439ae8aea839af6d9b84fe1384feb18de3d9d276
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>