ixgbe: cleanup configuration of EITRSEL and VF reset path

This change is meant to cleanup some of the code related to SR-IOV and the
interrupt registers.  Specifically I am moving the EITRSEL configuration
into the MSI-X configuration section instead of enablement.  Also I am
fixing the VF shutdown path since it had operations in the incorrect order.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>