[PKTGEN]: pktgen should not print info that it is spinning

when using pktgen to send delay packets the module prints repeatedly
to the kernel log:

sleeping for X
sleeping for X
...

This is probably just a debugging item left in and should not be
enabled for regular use of the module.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>