When enabling DCB the rings belonging to a q_vector on CPU 0 were not
reinitializing their DCA registers.  Upon closer inspection the issue was
that the q_vector CPU variable was left at 0 resulting in the driver not
updating the DCA registers.

In order to guarantee the DCA registers will be updated I am adding a
couple line change so that we initialize the CPU variable to -1 which will
force a DCA update the first time an interrupt fires on that q_vector.

In addition we were setting the CPU affinity hint to all CPUs when we were
not specifying a CPU.  Instead we should leave it as all zeros to avoid any
possible confusion about the fact that we shouldn't be giving a hint.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>