DSA: Check for sanity of input parameters

dsa_builtin_paramgen2 expects the L parameter to be greater than N,
otherwise the generation will get stuck in an infinite loop.

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>

(cherry picked from commit 3afd38b277a806b901e039c6ad281c5e5c97ef67)

(Merged from https://github.com/openssl/openssl/pull/7493)