ASoC: tas5720: add TAS5722 register support

Introduce a custom super-set register map and associated bit definitions
to allow driver access to all TAS5722 device functionality.

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