Enable modules for the BeagleBone and for the Raspberry Pi.
Revert ROOTDEVNAME change from previous commit.
Clear entire map structure including locks so that the
locks don't accidentally appear to have been already
initialized.

In particular, this fixes a consistent kernel crash on
armv6 with:
  panic: lock "vm map (user)" 0xc09cc050 already initialized
that appeared with r251709.

PR: arm/180820
Add pkgconf files for libusb.

Reviewed by:	hselasky
Bump __FreeBSD_version for the addition of libusb's pkgconf files.