ixgbe: fix EEH recovery during reset on PPC

EEh is not recovering in a resonable amount of time on PPC during
ixgbe_down().

Signed-off-by: Paul Larson <pl@us.ibm.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>