Bluetooth: Add missing mgmt_confirm_name command definition

This patch adds the necessary structs for the Confirm Name command. This
ensures that the protocol definitions are up to date with the latest
mgmt specification. The actual implementation of the command will follow
in a later patch-set.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>