Adding `Locked` field in the `showmap` output am: b6b594be27 am: c56df9585f am: 3e1fdaa976 am: f8deebd1fc

Original change: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/2182384

Change-Id: Ic066e3367c75988b1255b8e60ead4595b9a2b9bc
Signed-off-by: Automerger Merge Worker <[email protected]>