Bluetooth: Power off AMP controllers after setup phase

Bluetooth: Power off AMP controllers after setup phase

Even AMP controllers should be powered off after the setup phase. It
is not a good idea to keep AMP controllers powered on all the time
if they are not in use.

Power on of the AMP controller can either be done manually via
command line commands or directly via A2MP. Especially since there
is an indication in A2MP for powered down controllers that can
be activated.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>