[PATCH v9 5/5] drm/rockchip: Add dmc notifier in vop driver

when in ddr frequency scaling process, vop can not do enable or disable operation, since in dcf we check vop clock to see whether vop work. If vop work, dcf do ddr frequency scaling when vop in vblank status, and we need to read vop register to check whether vop go into vblank status. If vop not

[PATCH v9 5/5] drm/rockchip: Add dmc notifier in vop driver

when in ddr frequency scaling process, vop can not do enable or disable operation, since in dcf we check vop clock to see whether vop work. If vop work, dcf do ddr frequency scaling when vop in vblank status, and we need to read vop register to check whether vop go into vblank status. If vop not