msm_fb: display: add video mode dcs cmdlist support

Add video mode dcs command list support. This patch
make sure dcs commands committed while dsi video engine
is busy so that dcs command will be transmitted at beginning
of next BLLP.

Change-Id: I11b0214ee10f3b1ef33b1da4c8e577800068cb06
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>