ASoC: mpc8610: tell the CS4270 codec that it's the master

Commit ac601555 ("ASoC: Return early with -EINVAL if invalid dai format is
detected") requires the machine driver to tell the CS4270 codec driver
whether the CS4270 should be configured for master or slave operation.

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