msm: mdss: debug: dump dsi errors from xlog work queue

Dsi errors happen at interrupt context while xlog
dumps can only be called at normal priority. This change
makes sure that xlog registers dumps and panic happen
from a work queue during dsi erros to prevent slow
path errors.

Change-Id: Ib9928d653221d0dbb0b87a5965ef3c4b20ebb662
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>