e1000e: i219 fix unit hang on reset and runtime D3

e1000e: i219 fix unit hang on reset and runtime D3

Orabug: 21792108

Unit hang may occur if multiple descriptors are available in the rings
during reset or runtime suspend. This state can be detected by testing
bit 8 in the FEXTNVM7 register. If this bit is set and there are pending
descriptors in one of the rings, we must flush them prior to reset. Same
applies entering runtime suspend.

Signed-off-by: Yanir Lubetkin <yanirx.lubetkin@intel.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit ad851fbb73a3d6564707281aa253418ef6aab878)
Signed-off-by: Brian Maly <brian.maly@oracle.com>