io_uring: unite fill_cqe and the 32B version

io_uring: unite fill_cqe and the 32B version

We want just one function that will handle both normal cqes and 32B
cqes. Combine __io_fill_cqe_req() and __io_fill_cqe_req32(). It's still
not entirely correct yet, but saves us from cases when we fill an CQE of
a wrong size.

Fixes: cae2e6244e788 ("io_uring: enable CQE32")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8085c5b2f74141520f60decd45334f87e389b718.1655287457.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>