mdss: dsi: Add support to partial update

Add support to send DCS commands to set the partial update region
of interest(ROI) size. These commands will set the column/row start and end
coordinates based on the ROI size.

Change-Id: I3418472d9d622150c3cd7571b0b1e7a3482f5597
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>