Clean up trailing whitespace.

Submitted by: Andy Kosela
MFC after:    1 week
When reporting the user readable size, round up. Several SD cards not
only use SI units, but also are a couple of percent short. If you need
to know the exact size, diskinfo will return exact results.
When running the -m option to generate a newfs(8) command suitable for
recreating the filesystem, check for and output the -i, -k, and -l
options if appropriate.

Note the remaining deficiencies of the -m option in the dumpfs(8)
manual page. Specifically that newfs(8) options -E, -R, -S, and -T
options are not handled and that -p is not useful so is omitted.
Also document that newfs(8) options -n and -r are neither checked
for nor output but should be. The -r flag is needed if the filesystem
uses gjournal(8).

PR:           bin/163992
Reported by:  Dieter <freebsd@sopwith.solgatos.com>
Submitted by: Andy Kosela <akosela@andykosela.com>
MFC after:    1 week