RaspiDAC3 support

Signed-off-by: Jan Grulich <jan@grulich.eu>

config: fix RaspiDAC Rev.3x dependencies

Change depends to SND_BCM2708_SOC_I2S || SND_BCM2835_SOC_I2S
like the other I2S soundcard drivers.

Signed-off-by: Matthias Reichl <hias@horus.com>