Program SQ, MDQ, TL4 to TL2 transmit scheduler queues' DWRR
weight based on DWRR MTU programmed at NIX_AF_DWRR_RPM_MTU.
The DWRR MTU from admin function is retrieved via mbox.

On OcteaonTx2 silicon, admin function driver responds with DWRR
MTU as '1'. This helps to avoid silicon specific transmit
scheduler DWRR quantum/weight configuration logic.
Signed-off-by: NSunil Goutham <sgoutham@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>