fuzz/decoder.c: Limit the EVP_PKEY_param_check on DHX keys as well

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from #24126)

(cherry picked from commit 8d8a014)

fuzz/decoder.c

@@ -68,7 +68,8 @@ int FuzzerTestOneInput(const uint8_t *buf, size_t len)
          * Param check will take too long time on large DH parameters.
          * Skip it.
          */
-        if (!EVP_PKEY_is_a(pkey, "DH") || EVP_PKEY_get_bits(pkey) <= 8192)
+        if ((!EVP_PKEY_is_a(pkey, "DH") && !EVP_PKEY_is_a(pkey, "DHX"))
+            || EVP_PKEY_get_bits(pkey) <= 8192)
             EVP_PKEY_param_check(ctx);
 
         EVP_PKEY_public_check(ctx);