mm/kmemleak: compact kmemleak_object further

mm/kmemleak: compact kmemleak_object further

Patch series "mm/kmemleak: Minor cleanup & performance tuning".

This series contains 2 simple cleanup patches to slightly reduce memory
and performance overhead.

This patch (of 2):

With commit 56a61617dd22 ("mm: use stack_depot for recording kmemleak's
backtrace"), the size of kmemleak_object has been reduced by 128 bytes for
64-bit arches.  The replacement "depot_stack_handle_t trace_handle" is
actually just 4 bytes long leaving a hole of 4 bytes.  By moving up
trace_handle to another existing 4-byte hold, we can save 8 more bytes
from kmemleak_object reducing its overall size from 248 to 240 bytes.

Link: https://lkml.kernel.org/r/20240307190548.963626-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20240307190548.963626-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>