Bluetooth: Check for supported white list before issuing commands

The white list commands might not be implemented if the controller does
not actually support the white list. So check the supported commands
first before issuing these commands. Not supporting the white list is
the same as supporting a white list with zero size.

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