io_uring: don't use int for ABI

__kernel_rwf_t is defined as int, the actual size of which is
implementation defined. It won't go well if some compiler / archs
ever defines it as i64, so replace it with __u32, hoping that
there is no one using i16 for it.

Cc: [email protected]
Fixes: 2b188cc ("Add io_uring IO interface")
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/47c666c4ee1df2018863af3a2028af18feef11ed.1751412511.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

Author: isilence

include/uapi/linux/io_uring.h

@@ -50,7 +50,7 @@ struct io_uring_sqe {
 	};
 	__u32	len;		/* buffer size or number of iovecs */
 	union {
-		__kernel_rwf_t	rw_flags;
+		__u32		rw_flags;
 		__u32		fsync_flags;
 		__u16		poll_events;	/* compatibility */
 		__u32		poll32_events;	/* word-reversed for BE */