io_uring: add generic rsrc update with tags

Add IORING_REGISTER_RSRC_UPDATE, which also supports passing in rsrc
tags. Implement it for registered files.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d4dc66df204212f64835ffca2c4eb5e8363f2f05.1619356238.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>