mm: memcg: fix unit conversion for K() macro in OOM log

The commit bc8e51c ("mm: memcg: dump memcg protection info on oom or
alloc failures") added functionality to dump memcg protections on OOM or
allocation failures.  It uses K() macro to dump the information and passes
bytes to the macro.  However the macro take number of pages instead of
bytes.  It is defined as:

 #define K(x) ((x) << (PAGE_SHIFT-10))

Let's fix this.

Link: https://lkml.kernel.org/r/20251216212054.484079-1-shakeel.butt@linux.dev
Fixes: bc8e51c ("mm: memcg: dump memcg protection info on oom or alloc failures")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by: Chris Mason <clm@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: shakeelb

mm/memcontrol.c

@@ -5638,6 +5638,6 @@ void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg)
 		memcg = root_mem_cgroup;
 
 	pr_warn("Memory cgroup min protection %lukB -- low protection %lukB",
-		K(atomic_long_read(&memcg->memory.children_min_usage)*PAGE_SIZE),
-		K(atomic_long_read(&memcg->memory.children_low_usage)*PAGE_SIZE));
+		K(atomic_long_read(&memcg->memory.children_min_usage)),
+		K(atomic_long_read(&memcg->memory.children_low_usage)));
 }