Add pytest markers for core model and diffusion tests

Signed-off-by: 汪志鹏 <wangzhipeng628@gmail.com>
Signed-off-by: princepride <wangzhipeng628@gmail.com>

tests/diffusion/kernels/mot/test_mot_linear.py

@@ -48,6 +48,8 @@ from vllm_omni.diffusion.layers.mot.ops.mot_gemm import (
     get_best_mot_config,
 )
 
+pytestmark = [pytest.mark.core_model, pytest.mark.diffusion, pytest.mark.gpu]
+
 # ---------------------------------------------------------------------------
 # Constants
 # ---------------------------------------------------------------------------