emac: add missing support of 10mbit in emac/rgmii

In chips of emac/rgmii b'000' for 0/1 channel isn't suitable which
resulted in non working network interface in this mode.
Signed-off-by: Ivan Mikhaylov <ivan@ru.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/emac/rgmii.c

@@ -45,6 +45,7 @@
 
 /* RGMIIx_SSR */
 #define RGMII_SSR_MASK(idx)	(0x7 << ((idx) * 8))
+#define RGMII_SSR_10(idx)	(0x1 << ((idx) * 8))
 #define RGMII_SSR_100(idx)	(0x2 << ((idx) * 8))
 #define RGMII_SSR_1000(idx)	(0x4 << ((idx) * 8))
 
@@ -139,6 +140,8 @@ void rgmii_set_speed(struct platform_device *ofdev, int input, int speed)
 		ssr |= RGMII_SSR_1000(input);
 	else if (speed == SPEED_100)
 		ssr |= RGMII_SSR_100(input);
+	else if (speed == SPEED_10)
+		ssr |= RGMII_SSR_10(input);
 
 	out_be32(&p->ssr, ssr);