ASoC: WCD9304: Fix Headphone + Lineout concurrent audio playback, without test

During concurrent playback on headphone and lineout, it is observed that
headphone is enabled in class G mode. This causes incorrect routing to
lineout. Fix by making sure headphone does not operate in class G mode
when there is concurrent playback on headphone and lineout.
see: https://github.com/CyanogenMod/android_kernel_samsung_d2/commit/b92d6563ac2454032f973b9322b07ae8c1ee3032#L0R2022