sfc: Remove support for siena high priority queue

This also removes TC support code, since that was never supported for EF10.
TC support for EF100 is not handled from efx.c.

Signed-off-by: Martin Habets <habetsm.xilinx@gmail.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>