kyber: fix wrong strlcpy() size in trace_kyber_latency()

When copying to the latency type, we should be passing LATENCY_TYPE_LEN,
not DOMAIN_LEN (this isn't a problem in practice because we only pass
"total" or "I/O"). Fix it by changing all of the strlcpy() calls to use
sizeof().

Fixes: 6c3b7af1

 ("kyber: add tracepoints")
Reported-by: Jordan Glover <Golden_Miller83@protonmail.ch>
Tested-by: Jordan Glover <Golden_Miller83@protonmail.ch>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>