drm/msm: Add debugfs to disable hw err handling

Add a debugfs interface to ignore hw error irqs, in order to force
fallback to sw hangcheck mechanism.  Because the hw error detection is
pretty good on newer gens, we need this for igt tests to test the sw
hang detection.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Akhil P Oommen <akhilpo@codeaurora.org>
Link: https://lore.kernel.org/r/20211109181117.591148-6-robdclark@gmail.com


Signed-off-by: Rob Clark <robdclark@chromium.org>