Make sure the VSI has a netdev before trying to use it
in the debugfs netdev_ops commands.

Change-ID: I2d744fc0c32b3226534ce2cde171d9675c5440a6
Signed-off-by: NShannon Nelson <shannon.nelson@intel.com>
Signed-off-by: NCatherine Sullivan <catherine.sullivan@intel.com>
Tested-by: NKavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>