Bluetooth: hci_sync: Fix not indicating power state

When setting power state using legacy/non-mgmt API
(e.g hcitool hci0 up) the likes of mgmt_set_powered_complete won't be
called causing clients of the MGMT API to not be notified of the change
of the state.

Fixes: cf75ad8b ("Bluetooth: hci_sync: Convert MGMT_SET_POWERED")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Tedd Ho-Jeong An <tedd.an@intel.com>