openssh: fix static compilation

PIE and static doesn't work on Linux.

Fixes:
http://autobuild.buildroot.net/results/dce/dce0202e039f4636d68532c4aab8738938b76650/



Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>