It was observed that Tx performance was inconsistent across all queues
and/or VSIs and that it was directly connected to existing 9-layer
topology of the Tx scheduler.

Introduce new private devlink param - tx_scheduling_layers. This parameter
gives user flexibility to choose the 5-layer transmit scheduler topology
which helps to smooth out the transmit performance.

Allowed parameter values are 5 and 9.

Example usage:

Show:
devlink dev param show pci/0000:4b:00.0 name tx_scheduling_layers
pci/0000:4b:00.0:
  name tx_scheduling_layers type driver-specific
    values:
      cmode permanent value 9

Set:
devlink dev param set pci/0000:4b:00.0 name tx_scheduling_layers value 5
cmode permanent

devlink dev param set pci/0000:4b:00.0 name tx_scheduling_layers value 9
cmode permanent
Signed-off-by: Lukasz Czapnik <lukasz.czapnik@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Co-developed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>