drm/i915: Mark manually wedged engines as guilty

drm/i915: Mark manually wedged engines as guilty

Use the incoming value from debugfs/i915_wedged to select which engines
to marked as guilty in order to force us to reset those requests
(required to quickly bypass simulated hangs).

Testcase: igt/gem_exec_capture
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170325134735.30581-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>