xfs: add pre-content fsnotify hook for DAX faults

xfs has it's own handling for DAX faults, so we need to add the
pre-content fsnotify hook for this case. Other faults go through
filemap_fault so they're handled properly there.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/9eccdf59a65b72f0a1a5e2f2b9bff8eda2d4f2d9.1731684329.git.josef@toxicpanda.com