The read_trace_config() can dereference the line pointer after freeing
it on its error path. Avoid that.
This was found by Coverity Scan.
Signed-off-by: Vincent Stehlé <vincent.stehle@freescale.com>
Cc: Simon Glass <sjg@chromium.org>
 
                err = regcomp(&line->regex, tok, REG_NOSUB);
                if (err) {
+                       int r = regex_report_error(&line->regex, err,
+                                                  "compile", tok);
                        free(line);
-                       return regex_report_error(&line->regex, err, "compile",
-                                                 tok);
+                       return r;
                }
 
                /* link this new one to the end of the list */