ASoC: fix registration of the SoC card in the Freescale MPC8610 drivers

The Freescale MPC8610 driver was defining two SOC card (snd_soc_card)
structures, partially initializing each one, but registering only one of
them with ASoC.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>