ASoC: omap-abe-twl6040: Keep only one snd_soc_dai_link structure

There is no need to have two snd_soc_dai_link structure for the two setup
the machine driver supports.
We can just tell core to register only the first link if the DMIC link is
not in use on the device.

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