Add AArch64 support to qfilesystemwatcher_inotify.cpp

Based on a patch by Marcin Juszkiewicz <marcin@juszkiewicz.com.pl>,
licensed under CC0 (aka Public Domain) or BSD license.

Backported from qtbase, commit d5dcd6d16647e4ecac239fa26ade5963f0e3f933

Change-Id: I0d01a129c039250ac33dc5f984baec9595786211
Reviewed-by: Dmitry Shachnev <mitya57@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>