fanotify: Remove obsoleted fanotify_event_has_path()

All uses of fanotify_event_has_path() have
been removed since commit 9c61f3b5 ("fanotify: break up
fanotify_alloc_event()"), now it is useless, so remove it.

Link: https://lore.kernel.org/r/20220926023018.1505270-1-cuigaosheng1@huawei.com


Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>