lsvfs(1): Add EXAMPLES section

Add one simple exapmle and contrast some of the information using mount(8)

PR:
Submitted by:
Reported by:
Reviewed by: gbe@, yuripv@
Approved by: manpages (bcr@)
Obtained from:
MFC after:
MFH:
Relnotes:
Security:
Sponsored by:
Differential Revision: https://reviews.freebsd.org/D27544