ASoC: arizona: Set FLL to free-run before disabling

commit 3e68ce1bc72e5d6615677ec5a8b0a9bcb6c7a490 upstream.

The FLL must be placed into free-run mode before disabling
to allow it to entirely shut down.

Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>