dm: net: Adjust PHY interface to work with CONFIG_DM_ETH

When driver model is used for Ethernet a few functions are passed a udevice
instead of an eth_device. Also add a function to find a PHY type given its
name. This will be used to decode the device tree node.

Finally, put a phy_interface field in struct eth_pdata since this is an
important part of the platform data for Ethernet.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/common/miiphyutil.c b/common/miiphyutil.c
index 74812e6..c88c28a 100644
--- a/common/miiphyutil.c
+++ b/common/miiphyutil.c
@@ -11,6 +11,7 @@
  */
 
 #include <common.h>
+#include <dm.h>
 #include <miiphy.h>
 #include <phy.h>