msm: camera: isp: Fix bandwidth voting

Add minimum vote to be added to the bandwidth vote for
cobalt. Also, use the vfe clock rate when deciding the
bandwidth for both rdi as well as pix stream.

CRs-Fixed: 1065389
Change-Id: Ic142026e8963830cda5c2d607e6e96f66c39d1bb
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>