e1000e: i219 execute unit hang fix on every reset or power state transition

After testing various cases, the conclusion is that the fix MUST be
executed BEFORE any event that the HW is reset or transition to D3.
To fix that I moved the execution to the relevant places but per
Alexander Duyck's review, ensure now that the DMA is valid and was not
freed before manipulating the ring.

Signed-off-by: Yanir Lubetkin <yanirx.lubetkin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>