ASoC: wm8994: Don't lock CODEC mutex to do DAPM sync

DAPM now has a DAPM-level lock which it manages itself so we don't need
to take the CODEC mutex to call DAPM any more.  Also remove a redundant
call to snd_soc_dapm_sync(), jack reporting also triggers a DAPM sync.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>