ASoC: wcd9320: Add HD2 tuning coefficients for HPH path

Add 2nd Harmonic Distortion (HD2) tuning coefficients
for HPH path. HD2 coefficients get turned ON during HPH
enable and turned OFF during path tear down. Enabling HD2
coefficients would increase the Headphone PA efficiency during
audio playback.

Change-Id: I24bc053e6401d5b8f45dc62d88c7fe6a5ba01447
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>