mdp: mdss: Tune bandwidth and clock based on ROI

Calculate bandwidth and MDP clock requirement considering
the ROI submitted for a frame. When doing partial frame update
for smart panels, the data actually fetched for a pipe is not
always the full resolution of the buffer programmed. Use the
ROI passed to find out the region of fetching and calculate the
bandwidth and clock values accordingly.

Change-Id: I01f24f8fd9a42a2c4d705b8eb0a7658e79884175
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>