drm/msm/dsi-staging: fix ESD check command transfer failure

Currently DSI driver checks for last command flag to be set
in order to trigger the DMA command to HW. But for ESD check
command this flag is not set, so ESD check fails and causes
flicker on display due to ESD recovery process kicking in.
This change fixes the same by adding last command flag to
ESD check command wherever appropriate.

Change-Id: Ic46f7889fabb680960f63af5520f82e653f0e925
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>