ASoC: tlv320aic31xx: Merge init function into probe

The function aic31xx_device_init() is only called from probe and
does nothing that logically shouldn't be in probe, remove this
unneeded function call and move its code into probe where it was called.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>