io_uring/region: return negative -E2BIG in io_create_region()

This code accidentally returns positivie E2BIG instead of negative
-E2BIG.  The callers treat negatives and positives the same so this
doesn't affect the kernel.  The error code is returned to userspace via
the system call.

Fixes: dfbbfbf1 ("io_uring: introduce concept of memory regions")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/d8ea3bef-74d8-4f77-8223-6d36464dd4dc@stanley.mountain


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