ASoC: atmel: enable SOC_SSC_PDC and SOC_SSC_DMA in Kconfig

Allow SSC to be used on platforms described using audio-graph-card
in Device Tree.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/233d5461f4448df151755de7b69a0cd3ad310d5c.1566677788.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown <broonie@kernel.org>