net/ucc_geth: update riscTx and riscRx in ucc_geth

Change the definition of riscTx and riscRx to unsigned integer instead of
enum, and change their values to support 4 risc allocation if the qe has
4 RISC engines.

Signed-off-by: Haiying Wang <Haiying.Wang@freescale.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>