MFC r305023:

Avoid undefined behavior when calling va_start() in bnep_send_control(),
by making the 'type' parameter a plain unsigned.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix client mode. Pick up service availability changes.

Obtained from: NetBSD
MFC after: 1 month

Add btpand(8) daemon from NetBSD. This daemon provides support for
Bluetooth Network Access Point (NAP), Group Ad-hoc Network (GN) and
Personal Area Network User (PANU) profiles.

Obtained from: NetBSD
MFC after: 1 month