Fix cross-build from STABLE or older CURRENT.
Previously, zic and tzsetup were both listed as install tools and basic
bootstrap tools. Actually, tzsetup is an install tool while zic is a
non-basic bootstrap tool.
Fixes: 783c318fd118
Sponsored by: Klara, Inc.
Reviewed by: jrtc27, emaste
Differential Revision: https://reviews.freebsd.org/D38195