objtool, kcsan: Add explicit check functions to uaccess whitelist

Add explicitly invoked KCSAN check functions to objtool's uaccess
whitelist. This is needed in order to permit calling into
kcsan_check_scoped_accesses() from the fast-path, which in turn calls
__kcsan_check_access().  __kcsan_check_access() is the generic variant
of the already whitelisted specializations __tsan_{read,write}N.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/objtool/check.c

@@ -468,8 +468,10 @@ static const char *uaccess_safe_builtin[] = {
 	"__asan_report_store8_noabort",
 	"__asan_report_store16_noabort",
 	/* KCSAN */
+	"__kcsan_check_access",
 	"kcsan_found_watchpoint",
 	"kcsan_setup_watchpoint",
+	"kcsan_check_scoped_accesses",
 	/* KCSAN/TSAN */
 	"__tsan_func_entry",
 	"__tsan_func_exit",