openssh: remove redundant BSD license

The license statement already includes BSD-2-Clause and BSD-3-Clause, so
remove the redundant and ambiguous BSD license.

(From OE-Core rev: 5c0b03cd)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Mikko Rapeli <mikko.rapeli@bmw.de>
(cherry picked from commit 7eaab4b261017ae49926b4f18228a3af9906c19c)
Signed-off-by: Steve Sakoman <steve@sakoman.com>