stat: reduce arguments of add_*lat_sample() functions

stat: reduce arguments of add_*lat_sample() functions

The functions add_clat_sample(), add_lat_sample() and add_slat_sample()
have a rather large number of arguments, and some of the arguments are
members of the struct io_u. Pass io_u instead of those arguments to
reduce the number of arguments.

Some add_clat_sample() callers in engines/fileoperations.c do not have
io_u reference, then pass NULL instead of the io_u. This indicates to
use 0 values instead of the io_u fields.

While add_slat_sample() takes only struct thread_data * and struct
*io_u, add_clat_sample() and add_lat_sample() still require three more
arguments: 1) nsec is required because struct io_u does not have
completion time, 2) ddir is required to support fileoperations IO
engine, and 3) bs to record partial IO completion.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20240829085826.999859-2-shinichiro.kawasaki@wdc.com
Signed-off-by: Vincent Fu <vincent.fu@samsung.com>