drm/test: drm_exec: fix memory leak on object prepare

drm_exec_prepare_obj() and drm_exec_prepare_array() both reserve
dma-fence slots and hence a dma_resv_list without ever freeing it.

Make sure to call drm_gem_private_object_fini() for each GEM object
passed to drm_exec_prepare_obj()/drm_exec_prepare_array() throughout the
test to fix this up.

While at it, remove some trailing empty lines.

Fixes: 9710631c ("drm: add drm_exec selftests v4")
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230809225034.8803-1-dakr@redhat.comSigned-off-by: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/tests/drm_exec_test.c

@@ -125,8 +125,6 @@ static void test_duplicates(struct kunit *test)
 	drm_exec_fini(&exec);
 }
 
-
-
 static void test_prepare(struct kunit *test)
 {
 	struct drm_exec_priv *priv = test->priv;
@@ -145,6 +143,8 @@ static void test_prepare(struct kunit *test)
 			break;
 	}
 	drm_exec_fini(&exec);
+
+	drm_gem_private_object_fini(&gobj);
 }
 
 static void test_prepare_array(struct kunit *test)
@@ -165,6 +165,9 @@ static void test_prepare_array(struct kunit *test)
 					     1);
 	KUNIT_EXPECT_EQ(test, ret, 0);
 	drm_exec_fini(&exec);
+
+	drm_gem_private_object_fini(&gobj1);
+	drm_gem_private_object_fini(&gobj2);
 }
 
 static void test_multiple_loops(struct kunit *test)