drm/i915: Don't taint when using fault injection

It is not really unexpected to hit wedge on init this way.
We're already downgrading error printk when running with fault injection,
let's use the same approach for CI tainting.

v2: Don't check fault inject in trace dump (Chris)

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Petri Latvala <petri.latvala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200706144107.204821-3-michal@hardline.pl