io_uring: Change res2 parameter type in io_uring_cmd_done

Change the type of the res2 parameter in io_uring_cmd_done from ssize_t
to u64. This aligns the parameter type with io_req_set_cqe32_extra,
which expects u64 arguments.
The change eliminates potential issues on 32-bit architectures where
ssize_t might be 32-bit.

Only user of passing res2 is drivers/nvme/host/ioctl.c and it actually
passes u64.

Fixes: ee692a21 ("fs,io_uring: add infrastructure for uring-cmd")
Cc: stable@vger.kernel.org
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Tested-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Link: https://lore.kernel.org/r/20241203-io_uring_cmd_done-res2-as-u64-v2-1-5e59ae617151@ddn.com


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