ASoC: omap-abe-twl6040: Use the cpu_dai node to specify the platform driver

Now that the platform driver is registered with the cpu_dai's device we
can use the same node for it instead of the hardwired name.
We can also remove the cpu_dai_name and platform_name from the dai_link
struct since we only support DT boot on OMAP4/5

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>