ASoC: neo1973_wm8753: Remove scenario management code.

It has been proven to be inflexible to do scenario management in kernel space.

Since actual neo1973 board support has not been merged in mainline and this
patch has been in the neo1973 tree for some time now it should be safe to remove
this functionality without breaking existing userspace.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>