ASoC: omap-abe-twl6040: Use devm_snd_soc_register_card()

Using devm_snd_soc_register_card() can make the code
shorter and cleaner.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>