ASoC: mchp-i2s-mcc: Add support to select TDM pins

ASoC: mchp-i2s-mcc: Add support to select TDM pins

SAMA7G5's I2S-MCC has 4 pairs of DIN/DOUT pins. Since TDM only uses a
single pair of pins for synchronous capture and playback, the controller
needs to be told which of the pair is connected. This can be mentioned
using the "microchip,tdm-data-pair" property from DT. The property is
optional, useful only if TDM is used. If it's missing, DIN/DOUT 0 pins
will be used by default.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20210301170905.835091-6-codrin.ciubotariu@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>