drm/msm: Add fault-injection support

Intended as a way to trigger error paths in mesa.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/496710/
Link: https://lore.kernel.org/r/20220807172848.2432845-1-robdclark@gmail.com