blktrace_api.h: fix comment for struct blk_user_trace_setup

'struct blk_user_trace_setup' is passed to BLKTRACESETUP, not
BLKTRACESTART.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed