objtool: Add stackleak instrumentation to uaccess safe list

If a function has a large stack frame, the stackleak plugin adds a call
to stackleak_track_stack() after the prologue.

This function may be called in uaccess-enabled code.  Add it to the
uaccess safe list.

Fixes the following warning:

  vmlinux.o: warning: objtool: kasan_report+0x12: call to stackleak_track_stack() with UACCESS enabled
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/42e9b487ef89e9b237fd5220ad1c7cf1a2ad7eb8.1681320562.git.jpoimboe@kernel.org

tools/objtool/check.c

@@ -1279,6 +1279,8 @@ static const char *uaccess_safe_builtin[] = {
 	"__ubsan_handle_type_mismatch_v1",
 	"__ubsan_handle_shift_out_of_bounds",
 	"__ubsan_handle_load_invalid_value",
+	/* STACKLEAK */
+	"stackleak_track_stack",
 	/* misc */
 	"csum_partial_copy_generic",
 	"copy_mc_fragile",