[MIPS] Au1200: Make KGDB compile

AMD Au1200 SOC just doesn't have UART3, so KGDB won't even compile for it
as is, here's the fix to make KGDB use UART1.
    
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/mach-au1x00/au1000.h

@@ -1198,7 +1198,11 @@ extern au1xxx_irq_map_t au1xxx_irq_map[];
 
 /* UARTS 0-3 */
 #define UART_BASE                 UART0_ADDR
+#ifdef	CONFIG_SOC_AU1200
+#define UART_DEBUG_BASE           UART1_ADDR
+#else
 #define UART_DEBUG_BASE           UART3_ADDR
+#endif
 
 #define UART_RX		0	/* Receive buffer */
 #define UART_TX		4	/* Transmit buffer */