Merge branch 'perf_net_dropmonitor'

Ben Hutchings says:

====================
Somewhat surprisingly, the net_dropmonitor reporting script doesn't work
at all.  This series fixes it and then makes it slightly more efficient.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Neil Horman <nhorman@tuxdriver.com>