LF-4303 drm: rockchip: use the correct dev for function DRM_DEV_ERROR

After cdns DP API change, need use the correct dev for function DRM_DEV_ERROR
otherwise, there will be module driver build issue.

Signed-off-by: Jason Liu <jason.hui.liu@nxp.com>
Acked-by: Robby Cai <robby.cai@nxp.com>