ASoC: rockchip: Use codec of_node and dai_name for rt5514 dsp

Currently we are using codec name for rt5514 dsp dai link, use codec
of_node instead.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>