fix regression in "epoll: Keep a reference on files added to the check list"

[ Upstream commit 77f4689de17c0887775bb77896f4cc11a39bf848 ]

epoll_loop_check_proc() can run into a file already committed to destruction;
we can't grab a reference on those and don't need to add them to the set for
reverse path check anyway.

Change-Id: I9e9ef7d3e6f9f30b992dda31dcfa4cc92e097ba8
Tested-by: Marc Zyngier <maz@kernel.org>
Fixes: a9ed4a6560b8 ("epoll: Keep a reference on files added to the check list")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Git-commit: 8238ee93
Git-repo: https://android.googlesource.com/kernel/common/


Signed-off-by: Srinivasarao P <spathi@codeaurora.org>