ASoC: mioa701: convert to snd_soc_register_card API

The mioa701 board code is converted to the snd_soc_register_card()
and snd_soc_unregister_card() APIs.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>