msm: mdss: re-check dsi cmd transfer done interrupt

There is a possibility that irq trigger may get delayed in the
software for more than expected, in such cases the cmd done status
may have been updated in DSI isr status register. Add additional
check to see if the dma transfer is completed by reading this register
and checking the status.

Change-Id: Ia27ee162668949934c3e3cedc97e746832824f5c
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>