ixgbevf: Fix ordering of shutdown to correctly disable Rx and Tx

This patch updates the ordering of the shutdown path so that we attempt to
shutdown the rings more gracefully. Basically the big changes are that we
shutdown the main Rx filter in the case of Rx and we set the carrier_off
state in the case of Tx so that packets stop being delivered from outside
the driver.  Then we shut down interrupts and NAPI.  Finally we stop the
rings from performing DMA and clean them.  This is a bit more graceful than
the previous path.

CC: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>