ASoC: wcd9310: Update compander gain implementation

When compander is enabled, PA has no impact on the playback
path. In order to keep the output audio level consistently during
compander enabling and disabling so we have to apply the same
gain/attention in PA to digital gain to compensate the PA gain.

CRs-fixed: 456565
Change-Id: Idf760bac35b25aab419a23ce5803c68831850856
Signed-off-by: Kuirong Wang <kuirongw@codeaurora.org>