blkparse: add support sort program by io event

blkparse: add support sort program by io event

Displays each program's data sorted by program name or io event, like
Queued, Read, Write and Complete. When -S is specified the -s will be ignored.
The capital letters Q,R,W,C stand for KB, then q/r/w/c stand for IO.
The N is used for sorting programs by name, same to -s.

If you want to sort programs by how many data they queued, you can use:

blkparse -i sda.blktrace. -q -S Q -o sda.parse

Signed-off-by: Weiping Zhang <zhangweiping@didiglobal.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>