Instead of having various protocols provide <protocol>_supported()
functions, let's use IS_ENABLED() macro that works well in "if" statements.
Acked-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>