objtool, kcsan: Add memory barrier instrumentation to whitelist

Adds KCSAN's memory barrier instrumentation to objtool's uaccess
whitelist.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/objtool/check.c

@@ -849,6 +849,10 @@ static const char *uaccess_safe_builtin[] = {
 	"__asan_report_store16_noabort",
 	/* KCSAN */
 	"__kcsan_check_access",
+	"__kcsan_mb",
+	"__kcsan_wmb",
+	"__kcsan_rmb",
+	"__kcsan_release",
 	"kcsan_found_watchpoint",
 	"kcsan_setup_watchpoint",
 	"kcsan_check_scoped_accesses",