Use CONFIG_ULI526X as MPC8610HPCD default Ethernet driver

Use driver/net/uli526x.c as MPC8610HPCD default Ethernet driver.
Remove unused ethernet CONFIG_ options.

Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Acked-by: Jon Loeliger <jdl@freescale.com>

include/configs/MPC8610HPCD.h

@@ -312,11 +312,8 @@
 #define CONFIG_CMD_NET
 #define CONFIG_PCI_PNP		/* do pci plug-and-play */
 
-#define CONFIG_RTL8139
-#define CONFIG_SK98
-#define CONFIG_EEPRO100
-#define CONFIG_TULIP
-#ifdef CONFIG_TULIP
+#define CONFIG_ULI526X
+#ifdef CONFIG_ULI526X
 #define CONFIG_ETHADDR   00:E0:0C:00:00:01
 #endif