BACKPORT: /proc/pid/smaps: add mseal info for vma

Add sl in /proc/pid/smaps to indicate vma is sealed

Link: https://lkml.kernel.org/r/20240614232014.806352-2-jeffxu@google.com


Fixes: 8be7258a ("mseal: add mseal syscall")
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Röttger <sroettger@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 399ab86e)

Change-Id: I5ce97e9efae373c404b3d6678d608d9955fbfb8e
Signed-off-by: Jeff Xu <jeffxu@google.com>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>