L2CA_SetDesireRole() function

* Function L2CA_SetDesireRole * Description This function sets the desire role for L2CAP. * If the new role is L2CAP_ROLE_ALLOW_SWITCH, allow switch on * HciCreateConnection. * If the new role is L2CAP_ROLE_DISALLOW_SWITCH, do not allow switch on * HciCreateConnection. * If the new role is a valid role (HCI_ROLE_MASTER or HCI_ROLE_SLAVE), * the desire role is set to the new value. Otherwise, it is not changed. * Returns the new (current) role