Clean up unit prefixes for binary multiples in comments and prints
Change comments and prints that are referring to values based on
binary multiples to use IEC 80000-13 prefixes for binary
multiples rather than SI prefixes for decimal multiples (e.g.,
KiB, MiB, and GiB rather than KB, MB, and GB).
Includes a fix for the rate_min print that was printing "KB/s"
although it was really printing bytes per second.
Includes a fix for goptions confusing the PB and TB units (while
changing them to PiB and TiB).
Signed-off-by: Jens Axboe <axboe@fb.com>