Bluetooth: Restrict SSP setting changes to BR/EDR enabled controllers

Only when BR/EDR is supported and enabled, allow changing of the SSP
setting. Just checking if the hardware supports SSP is not enough
since it might be the case that BR/EDR is disabled.

In the case that BR/EDR is disabled, but SSP supported by the
controller the not supported error message is now returned.

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