ASoC: wcd9306: Update DEM-2 mux input based on codec type

Tapan codec has two variants wcd9306 and wcd9302.
WCD9302 codec does not have compander block and hence
the DEM-2 mux input should always be selected to NZ_SHAPER.
Selecting the mux to CLASS_H_BUFFER would cause audio mute
if the CP clock is not enabled, which is the case when RX2
interpolator path is shared for HPHR and LO.

Change-Id: I7ea00a30d0554cc9e012fd0975c9a28e7cdf12f0
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>