Bluetooth: Differentiate LE User Pairing Responses

Low Energy (LE) pairing responses must be recognized and handled
differently from BR/EDR pairing responses. BR/EDR responses are
handled via HCI commands by the LMP layer, and LE responses are
handled by the Host.

Signed-off-by: Brian Gix <bgix@codeaurora.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>