This commit incorporates findings from
https://lkml.org/lkml/2016/4/25/594

The function has been modified to make sure we hold
the dev lock when accessing the net device pointer.
Acked-by: NJim Baxter <jim_baxter@mentor.com>
Signed-off-by: NHarish Jenny K N <harish_kandiga@mentor.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>