https://bugzilla.kernel.org/show_bug.cgi?id=214621
--- Comment #14 from Erhard F. (erhard_f@mailbox.org) --- (In reply to Lang Yu from comment #12)
The warning was just merged into mainline 5.15.0 on Tue Nov 2 16:47:49 2021(commit 56d33754481f). Not sure Erhard F.'s build contains this warning.
I applied your patch on top of v5.15 after its' release which was 2021-10-31 not on git master.