lib/utmp.c: Don't check for NULL before free(3)

free(NULL) is valid; there's no need to check for NULL.  Simplify.

Fixes: 5178f8c5af ("utmp: call prepare_utmp() even if utent is NULL")
Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/utmp.c

@@ -374,10 +374,8 @@ int update_utmp (const char *user,
 
 	(void) setutmp  (ut);	/* make entry in the utmp & wtmp files */
 
-	if (utent != NULL) {
-		free (utent);
-	}
-	free (ut);
+	free(utent);
+	free(ut);
 
 	return 0;
 }