ASoC: da7219: Improve pop/click performance for sensitive HPs

Currently on some headsets slight pops can be heard during DAPM
power-up/down. This can also be witnessed during the HP detect
procedure. This patch addresses the issue by adjusting DAPM power
sequencing slightly, the introduction of delays and use of
minimum HP gain to avoid such noise artefacts.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@kernel.org>