Implement basic support for the USB host controller found in the
SAF1761 chip, supporting BULK and CONTROL endpoints. This code is not
yet tested.

Sponsored by:	DARPA, AFRL
Rename "saf1761_dci_xxx" into "saf1761_otg_xxx" to reflect that this
driver supports both host and device side mode.

Sponsored by:	DARPA, AFRL
Fix a compile warning about unused variable.

Sponsored by:	DARPA, AFRL
Cancel DAD for an ifa when the ifp has ND6_IFF_IFDISABLED as early as
possible and do not clear IN6_IFF_TENTATIVE.  If IFDISABLED was accidentally
set after a DAD started, TENTATIVE could be cleared because no NA was
received due to IFDISABLED, and as a result it could prevent DAD when
manually clearing IFDISABLED after that.
Remove old files.

Sponsored by:	DARPA, AFRL