new at91_emac network driver (NET_MULTI api)

* add's at91_emac (AT91RM9200) network driver (NET_MULTI api)
* enable driver with CONFIG_DRIVER_AT91EMAC
* generic PHY initialization
* modify AT91RM9200 boards to use NET_MULTI driver
* the drivers has been tested with LXT971 Phy and DM9161 Phy at
  MII and RMII interface

Signed-off-by: Jens Scharsig <js_at_ng@scharsoft.de>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/include/configs/cpuat91.h b/include/configs/cpuat91.h
index 8746f70..e872fe9 100644
--- a/include/configs/cpuat91.h
+++ b/include/configs/cpuat91.h
@@ -128,7 +128,13 @@
 #define CONFIG_SYS_MEMTEST_END			\
 	(CONFIG_SYS_MEMTEST_START + PHYS_SDRAM_SIZE - 512 * 1024)
 
-#define CONFIG_DRIVER_ETHER			1
+#define CONFIG_NET_MULTI		1
+#ifdef CONFIG_NET_MULTI
+#define CONFIG_DRIVER_AT91EMAC		1
+#define CONFIG_SYS_RX_ETH_BUFFER	8
+#else
+#define CONFIG_DRIVER_ETHER		1
+#endif
 #define CONFIG_NET_RETRY_COUNT			20
 #define CONFIG_AT91C_USE_RMII			1
 #define CONFIG_PHY_ADDRESS			(1 << 5)