net: ucc_geth, increase no. of HW RX descriptors

In a busy network we see ucc_geth is dropping RX pkgs every now
and then. Increase the RX queues HW descriptors from
16 to 32 to deal with this.
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/ucc_geth.h

@@ -877,7 +877,7 @@ struct ucc_geth_hardware_statistics {
 
 /* Driver definitions */
 #define TX_BD_RING_LEN                          0x10
-#define RX_BD_RING_LEN                          0x10
+#define RX_BD_RING_LEN                          0x20
 
 #define TX_RING_MOD_MASK(size)                  (size-1)
 #define RX_RING_MOD_MASK(size)                  (size-1)