drm/msm/dsi-staging: handle spurious error interrupts

DSI controller can trigger spurious error interrupts
during ESD attack scenarios. Add a check for such spurious
interrupts during error handling.

Change-Id: Iab86e34a7d94991de5c2ad1c62404f1dee1c81b6
Signed-off-by: Shashank Babu Chinta Venkata <sbchin@codeaurora.org>