Fix a bug where ethtool set-channels would return failure when configuring
only one Rx queue.

Change-ID: Id833c48c17d71e352b30f3249f6acf9e7aaec57e
Signed-off-by: NAnjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: NKavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>