drm/i915/selftests: Prepare dma-buf tests for obj->mm.lock removal.

Use pin_pages_unlocked() where we don't have a lock.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-46-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c

@@ -194,7 +194,7 @@ static int igt_dmabuf_import_ownership(void *arg)
 
 	dma_buf_put(dmabuf);
 
-	err = i915_gem_object_pin_pages(obj);
+	err = i915_gem_object_pin_pages_unlocked(obj);
 	if (err) {
 		pr_err("i915_gem_object_pin_pages failed with err=%d\n", err);
 		goto out_obj;