proc: Use for_each_thread in do_io_accounting

This is a little bit tricky as the loop is currently formulated in such a way
that it skips the curren thread (task).  Add an explicit skip of when
t == task to preserve that needed behavior and document why that is
happening.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
1 file changed