Backport mm/page_alloc: add a missing mm_page_alloc_zone_locked() tracepoint to 5.10

Hello,

We're seeing a mysterious KASAN complaint without ce8f86ee94fa in Linux 5.10.11:

* https://lkml.org/lkml/2021/1/28/1344

It would be great to backport it to save others the same headache.

Thanks!