Remove only-works-on-amd64 restriction.

Sponsored by:	The FreeBSD Foundation
Add ZEDBOARD.

Tested against:	stable/10@r262905 (build only)
Sponsored by:	The FreeBSD Foundation
Merge r262907 from ^/projects/release-embedded:
  Add ZEDBOARD support for release builds.

Sponsored by:	The FreeBSD Foundation