FIPS: Fix compiler errors in rsa_chk.c when building with `-DFIPS_MODE`

Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8843)

crypto/rsa/rsa_chk.c

@@ -25,11 +25,9 @@ int RSA_check_key(const RSA *key)
 int RSA_check_key_ex(const RSA *key, BN_GENCB *cb)
 {
 #ifdef FIPS_MODE
-    if (!(rsa_sp800_56b_check_public(key)
+    return rsa_sp800_56b_check_public(key)
                && rsa_sp800_56b_check_private(key)
-            && rsa_sp800_56b_check_keypair(key, NULL, -1, RSA_bits(key))
-        return 0;
-
+               && rsa_sp800_56b_check_keypair(key, NULL, -1, RSA_bits(key));
 #else
     BIGNUM *i, *j, *k, *l, *m;
     BN_CTX *ctx;