Log Message:
security/openssh: Only disable fido on SunOS

Relative to revision 1.40, this disables the fido option on SunOS,
because libfido2 doesn't build there.  This differs from the previous
commits, which disabled fido everywhere but NetBSD, and then
everywhere but NetBSD and Darwin.  Surely it works on Linux, and in
general it ought to work everywhere.