lms.c: Updated documentation

Signed-off-by: Minos Galanakis <[email protected]>

library/lms.c

@@ -101,7 +101,7 @@ static int create_merkle_leaf_value(const mbedtls_lms_parameters_t *params,
     size_t output_hash_len;
     unsigned char r_node_idx_bytes[4];
 
-    /* Always zeroize the output buffer to avoid undefined behavior at an early exit */
+    /* Always zeroize the output buffer because it may contain data from the previous invocation */
     memset(out, 0, MBEDTLS_LMS_M_NODE_BYTES(params->type));
 
     op = psa_hash_operation_init();