io_uring/filetable: ensure node switch is always done, if needed

No upstream patch exists for this issue, as it was introduced by
a stable backport.

A previous backport relied on other code changes in the io_uring file
table and resource node handling, which means that sometimes a resource
node switch can get missed. For 6.1-stable, that code is still in
io_install_fixed_file(), so ensure we fall-through to that case for the
success path too.

Fixes: a3812a47 ("io_uring: drop any code related to SCM_RIGHTS")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>