drm/i915: Remove a defunct BUG_ON

This used to check the precondition that all fences were to be located
in a mappable area, redundant now as those two parameters are combined
into one.

After pinning, we assert that the buffer is bound into the desired
region.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_gem.c

@@ -4248,7 +4248,6 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
 	int ret;
 
 	BUG_ON(obj->pin_count == DRM_I915_GEM_OBJECT_MAX_PIN_COUNT);
-	BUG_ON(map_and_fenceable && !map_and_fenceable);
 	WARN_ON(i915_verify_lists(dev));
 
 	if (obj->gtt_space != NULL) {