signature-params: Provide option for maximum RSA/PSS salt length

However, the length now has to be resolved early, so we don't operate on
the negative constant values e.g. when generating the encoding.

src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_private_key.c

@@ -135,11 +135,7 @@ static bool set_pss_params(private_private_key_t *this, JNIEnv *env,
 	{
 		return FALSE;
 	}
-	slen = hasher_hash_size(pss->hash);
-	if (pss->salt_len > RSA_PSS_SALT_LEN_DEFAULT)
-	{
-		slen = pss->salt_len;
-	}
+	slen = pss->salt_len;
 	obj = (*env)->NewObject(env, cls, method_id, jhash, jmgf1, obj, slen, 1);
 	if (!obj)
 	{