Revert "fanotify: limit number of event merge attempts"

Temporarily revert commit ad3ea167 ("fanotify: limit number of
event merge attempts") to enable subsequent upstream commits to
apply and build cleanly.

Stable-dep-of: 8988f11a ("fanotify: reduce event objectid to 29-bit hash")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>