drm/i915: Inject load failure inside intel_engines_init_mmio

We need extra load failure point to better test error path in
i915_driver_init_mmio.
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
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/20181011130008.24640-2-michal.wajdeczko@intel.com

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -337,6 +337,9 @@ int intel_engines_init_mmio(struct drm_i915_private *dev_priv)
 	WARN_ON(ring_mask &
 		GENMASK(BITS_PER_TYPE(mask) - 1, I915_NUM_ENGINES));
 
+	if (i915_inject_load_failure())
+		return -ENODEV;
+
 	for (i = 0; i < ARRAY_SIZE(intel_engines); i++) {
 		if (!HAS_ENGINE(dev_priv, i))
 			continue;