i40e: Fix NPAR Tx Scheduler init

Recent changes to the driver initialization have caused the BW
configurations to not take effect.  We use a BW configuration read and
write back to "kick" the Tx scheduler into action.

Change-ID: I94ab377c58d3a3986e3de62b6c199be3fd2ee5e6
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>