mm: remove reference to destructor in comment in calculate_sizes()

mm: remove reference to destructor in comment in calculate_sizes()

The commit that removed support for destructors from kmem_cache_alloc()
never removed the comment regarding destructors in the explanation of the
possible relocation of the free pointer in calculate_sizes().

Link: https://lkml.kernel.org/r/20251021110004.2209008-1-william.kucharski@oracle.com
Fixes: 20c2df83d25c ("mm: Remove slab destructors from kmem_cache_create().")
Signed-off-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Christoph Lameter (Ampere) <cl@gentwo.org>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>