libssh2: update 1.10.0 -> 1.11.0

License-update: copyright years

Enable static libs as some tests need them.

Fix up ptests; the set being run is the same.
test_simple is statically linked, hence DISABLE_STATIC is overriden.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>