iotop: add major/minor fault stats

Provide major/minor fault stats.

It would be helpful to see per-process memory consumption speed.
It is also useful to see read IO caused by major fault, which
is critical for app latency.

Bug: 114325007
Test: iotop -h
Test: iotop -m 10 -s faults
Change-Id: If9670a4efe76bcd67b9caedb3427b69896ebed17
Signed-off-by: Minchan Kim <minchan@google.com>
[Added sorter for major+minor faults]
Signed-off-by: Sandeep Patil <sspatil@google.com>
3 files changed