ioc->ioc_data is rcu protectd, so uses correct API to access it.
This doesn't change any behavior, but just make code consistent.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Cc: stable@kernel.org # after ab4bd22dSigned-off-by: NJens Axboe <jaxboe@fusionio.com>