i40e: I40E_FLAG_MQ_ENABLED is not used

Remove references to I40E_FLAG_MQ_ENABLED from the code
as it doesn't seem to be used anywhere.

Change-Id: I4c89fb65b2cdd26fbb0c58fccbbb4b03f0e5f1b3
Signed-off-by: Neerav Parikh <Neerav.Parikh@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>