io-uring: Make tracepoints consistent.

This makes the io-uring tracepoints consistent. Where it makes sense
the tracepoints start with the following four fields:
- context (ring)
- request
- user_data
- opcode.

Signed-off-by: Stefan Roesch <shr@fb.com>
Link: https://lore.kernel.org/r/20220214180430.70572-3-shr@fb.com


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