feat(mt8196): add CPU QoS stub implementation

Add stub implementation for CPU QoS driver.

Change-Id: I1296aaff34c860ac878ad2ac26b511fb2411510e
Signed-off-by: Yidi Lin <yidilin@chromium.org>
diff --git a/plat/mediatek/include/mtk_bl31_interface.h b/plat/mediatek/include/mtk_bl31_interface.h
index 2216553..a74fa17 100644
--- a/plat/mediatek/include/mtk_bl31_interface.h
+++ b/plat/mediatek/include/mtk_bl31_interface.h
@@ -81,4 +81,8 @@
 enum mtk_bl31_status emi_mpu_set_aid(unsigned int region, unsigned int num);
 void emi_protection_init(void);
 
+/* CPU QoS interfaces */
+void cpu_qos_change_dcc(uint32_t on, uint32_t is_auto);
+void *cpu_qos_handle_cluster_on_event(const void *arg);
+
 #endif /* __MTK_BL31_INTERFACE_H__ */