net: ibm_newemac: convert it to use of_get_phy_mode

The patch extends 'enum phy_interface_t' and of_get_phy_mode a little
bit with PHY_INTERFACE_MODE_NA and PHY_INTERFACE_MODE_SMII added,
and then converts ibm_newemac net driver to use of_get_phy_mode
getting phy mode from device tree.

It also resolves the namespace conflict on phy_read/write between
common mdiobus interface and ibm_newemac private one.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David Miller <davem@davemloft.net>
diff --git a/include/linux/phy.h b/include/linux/phy.h
index ad51863..54fc413 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -53,6 +53,7 @@
 
 /* Interface Mode definitions */
 typedef enum {
+	PHY_INTERFACE_MODE_NA,
 	PHY_INTERFACE_MODE_MII,
 	PHY_INTERFACE_MODE_GMII,
 	PHY_INTERFACE_MODE_SGMII,
@@ -62,7 +63,8 @@
 	PHY_INTERFACE_MODE_RGMII_ID,
 	PHY_INTERFACE_MODE_RGMII_RXID,
 	PHY_INTERFACE_MODE_RGMII_TXID,
-	PHY_INTERFACE_MODE_RTBI
+	PHY_INTERFACE_MODE_RTBI,
+	PHY_INTERFACE_MODE_SMII,
 } phy_interface_t;