Bluetooth: Fix checking for valid device class values

The two lowest bits of the minor device class value are reserved and
should be zero, and the three highest bits of the major device class
likewise. The management code should therefore test for this and return
a proper "invalid params" error if the condition is not met.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>