LED blinking rate is based on tx/rx traffic, the most reasonable place
to do it is after update the traffic byte counts

This fixes the recent LED blinking breakage on 3945 introduced by "iwlwifi:
separate led function from statistic notification"
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Tested-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>