openssh: Add a workaround for ICE on powerpc64le

openssh: Add a workaround for ICE on powerpc64le

Fixes [YOCTO #15415]

The new openssh version has an ICE on powerpc64le similar to the one on
mips/mips64[1]. By adding flag "--without-hardening" to "./configure",
compiler option "-fzero-call-used-regs" will be removed when compiling. This
prevents certain functions from triggering the following ICE:

unimplemented: argument 'used' is not supported for '-fzero-call-used-regs' on this target

References
[1] https://git.openembedded.org/openembedded-core/commit/?id=5b290566519a87c563945a033cb49863317ad63d

Signed-off-by: William Lyu <William.Lyu@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>