platform: msm_shared: fix dual dsi dsc config issues

The DSC parameters calculation did not take dual dsi into account
leading to wrong calculations. And only single DSC was getting
configured due to wrong flag checks. Make changes to configure
both the dsc for dual dsi and fix DSC parameters calculation.

Change-Id: I6de312ae3448ded83a222deaabe9b8fe9fd92db9
2 files changed