msm: mdss: Reset compression config after dynamic DSC off

When dynamically switching modes from DSC on to off, the
compression mode control register should be set to 0 to
avoid corruption on the output.

Change-Id: Id4387063b767bf0f307c13831b9c6ecc31c20650
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>