Bluetooth: Fix REJECTED vs NOT_SUPPORTED mgmt responses

The REJECTED management response should mainly be used when the adapter
is in a state where we cannot accept some command or a specific
parameter value. The NOT_SUPPORTED response in turn means that the
adapter really cannot support the command or parameter value.

This patch fixes this distinction and adds two helper functions to
easily get the appropriate LE or BR/EDR related status response.

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