mm: vmscan: reset sc->priority on retry

The commit 6be5e186fd65 ("mm: vmscan: restore incremental cgroup
iteration") added a retry reclaim heuristic to iterate all the cgroups
before returning an unsuccessful reclaim but missed to reset the
sc->priority.  Let's fix it.

Link: https://lkml.kernel.org/r/20240529154911.3008025-1-shakeel.butt@linux.dev


Fixes: 6be5e186fd65 ("mm: vmscan: restore incremental cgroup iteration")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by:  <syzbot+17416257cb95200cba44@syzkaller.appspotmail.com>
Tested-by:  <syzbot+17416257cb95200cba44@syzkaller.appspotmail.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>