fbdev: msm: snapshot of mdss driver

This is a snapshot of mdss driver from msm-4.14
as of commit '15e898828d1e (fbdev: msm: Avoid UAF
in mdss_dsi_cmd_write)'.

Change-Id: I16fe01fd45855d5c268c210ec61f09c6fa625761
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>
Signed-off-by: Althaf Neelanchirayil <aneelanc@codeaurora.org>