ASoC: twl6040: Add back support for legacy mode

The legacy mode has been accidentaly removed by commit:
ASoC: twl6040: add all ABE DAIs

Add back the twl6040-hifi dai.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>