Address coverity issue 1655294

Fixes: openssl/project#1267

Signed-off-by: Norbert Pocs <norbertp@openssl.org>

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from openssl#27989)

Author: jogme

crypto/ml_kem/ml_kem.c

@@ -1678,15 +1678,15 @@ ML_KEM_KEY *ossl_ml_kem_key_dup(const ML_KEM_KEY *key, int selection)
     void *tmp_pub;
     void *tmp_priv;
 
+    if (key == NULL)
+        return NULL;
     /*
      * Partially decoded keys, not yet imported or loaded, should never be
      * duplicated.
      */
     if (ossl_ml_kem_decoded_key(key))
         return NULL;
 
-    if (key == NULL)
-        return NULL;
     else if ((ret = OPENSSL_memdup(key, sizeof(*key))) == NULL)
         return NULL;