disp: msm: read mdp intf line count and trigger dma accordingly

when a broadcast DSI command is scheduled, the command can get
triggered close to the schedule line. This might cause DMA
timeout. This change reads the video line count from
MDP_INTF_LINE_COUNT register and checks whether DMA trigger
happens close to the schedule line. If it is not close to the
schedule line, then DMA command transfer is triggered.

Change-Id: Ida92e63e46b4cc703d57ce24097834f810776aa8
Signed-off-by: Harigovindan P <harigovi@codeaurora.org>