io_uring: temporarily disable registered waits

Disable wait argument registration as it'll be replaced with a more
generic feature. We'll still need IORING_ENTER_EXT_ARG_REG parsing
in a few commits so leave it be.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/70b1d1d218c41ba77a76d1789c8641dab0b0563e.1731689588.git.asml.silence@gmail.com


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