msm: mdss: enable MRPS command for short read commands

Currently, we specify the size of payload that the panel needs
to send back via the MRPS command only for DCS/Generic long
read commands. Enable the MRPS command to be sent for short
commands also based on the return length of the payload expected.

Change-Id: I634a8e5d12a8ea8d0a8118f360aef27610b21c9c
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>