ALSA: ASoC - fix DMA channel selection in Freescale MPC8610 sound drivers

On the Freescale MPC8610, SSI1 is hard-coded to use DMA channels 0 and 1
for playback and capture, and SSI2 is hard-coded to use DMA channels 2 and 3.
This patch fixes the fabric driver so that it uses the right channels.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>