docs/101271: serial console documentation implies kernel rebuild required -- doesn't mention device hints

[remko at FreeBSD.org]

Synopsis: serial console documentation implies kernel rebuild required -- doesn't mention device hints

Responsible-Changed-From-To: remko->freebsd-doc
Responsible-Changed-By: remko
Responsible-Changed-When: Thu Sep 27 07:43:24 UTC 2012
Responsible-Changed-Why: 
I see that I cannot do this in reasonable time, reassign to the pool

http://www.freebsd.org/cgi/query-pr.cgi?pr=101271