ASoC: wm_adsp: Move core_ena to be co-located with start bit

Many firmwares do not wait for the start bit before they begin
processing audio, whilst this is a bug on the firmware side there are
too many such firmwares in the wild to ignore the situation. This patch
moves the core enable to happen at same time as the start, the firmware
looses the ability to overlap its own startup with the audio path bring
up but we ensure that all firmwares behave.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>