ASoC: WCD9304: Fix Headphone + Lineout concurrent audio playback

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.

CRs-fixed: 421247
Change-Id: Ib1f38deb453d6dbbcf86f69a117e6dc812b61546
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>