drm/msm/dsi-staging: add error handling support to DSI driver

Add functions to handle and recover from various DSI errors
in DRM DSI driver. The errors that are currently handled are
DSI FIFO OVERFLOW, FIFO UNDERFLOW, DSI BTA TIMEOUT and
DSI LP/RX TIMEOUT.

Change-Id: Ifc4eeaf01b3b5204b26745b6cc2dcffb71cb3f57
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>