REMOVE OMAP LEGACY CODE: Remove old tlv320aic23.c code

All omap audio development must use ASoC driver as suggested by
David Brownell.

Please see sound/soc/omap. For patches, please send them against
the mainline tree to the alsa list with linux-omap list Cc'd.

See also the previous patch 4a6f6c8336db39d134b42b0ba083e79ed7fd536b.

Signed-off-by: Tony Lindgren <tony@atomide.com>