ASoC: Initial WM8962 DSP2 support

The WM8962 features a DSP providing a number of signal processing
features including HD Bass and Virtual Surround Sound (VSS).  Enable
initial support for this, allowing users to enable and disable the
algorithms using the default coefficient sets.  Further patches will
add support for runtime configuration of the DSP coefficients.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>