msm: vidc: Disable DCVS when Turbo mode is enabled

When clients enabled Turbo mode, it is expected that Venus runs
at Turbo frequency. But due to DCVS it may go to Nominal which is
different from clients expectation. Hence disable DCVS when Turbo
mode is enabled.

Change-Id: Ia1536cf5d888b9db6591ad5058f09fdccce3ca96
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>