drm/ttm: fix locking in test ttm_bo_validate_no_placement_signaled

The test works even without it, but lockdep starts screaming when it is
activated.

Trivially fix it by acquiring the lock before we try to allocate
something.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250710144129.1803-1-christian.koenig@amd.com

Author: ChristianKoenigAMD

drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c

@@ -542,14 +542,15 @@ static void ttm_bo_validate_no_placement_signaled(struct kunit *test)
 		bo->ttm = old_tt;
 	}
 
-	err = ttm_resource_alloc(bo, place, &bo->resource, NULL);
-	KUNIT_EXPECT_EQ(test, err, 0);
-	KUNIT_ASSERT_EQ(test, man->usage, size);
-
 	placement = kunit_kzalloc(test, sizeof(*placement), GFP_KERNEL);
 	KUNIT_ASSERT_NOT_NULL(test, placement);
 
 	ttm_bo_reserve(bo, false, false, NULL);
+
+	err = ttm_resource_alloc(bo, place, &bo->resource, NULL);
+	KUNIT_EXPECT_EQ(test, err, 0);
+	KUNIT_ASSERT_EQ(test, man->usage, size);
+
 	err = ttm_bo_validate(bo, placement, &ctx);
 	ttm_bo_unreserve(bo);