ml507: Fix Xilinx uartlite driver hang

The default configuration for ml507 will generate a hang() in the
Xilinx uartlite driver.

userial_ports[] in drivers/serial/serial_xuartlite.c does not get
initialized properly. CONFIG_SERIAL_BASE is unused.
XILINX_UARTLITE_BASEADDR is used instead.

Signed-off-by: Rommel Custodio <sessyargc+uboot@gmail.com>

include/configs/xilinx-ppc.h

@@ -118,7 +118,7 @@
 /* serial communication */
 #ifdef XPAR_UARTLITE_0_BASEADDR
 #define CONFIG_XILINX_UARTLITE
-#define CONFIG_SERIAL_BASE		XPAR_UARTLITE_0_BASEADDR
+#define XILINX_UARTLITE_BASEADDR	XPAR_UARTLITE_0_BASEADDR
 #define CONFIG_BAUDRATE			XPAR_UARTLITE_0_BAUDRATE
 #define CONFIG_SYS_BAUDRATE_TABLE	{ CONFIG_BAUDRATE }
 #else