MPC837XERDB: fix warning: "CONFIG_SYS_MONITOR_LEN" redefined

Signed-off-by: Wolfgang Denk <wd@denx.de>

include/configs/MPC837XERDB.h

@@ -230,7 +230,6 @@
 #endif
 
 #define CONFIG_SYS_MONITOR_LEN		(384 * 1024) /* Reserve 384 kB for Mon */
-#define CONFIG_SYS_MONITOR_LEN		(320 * 1024) /* Reserve 320 kB for Mon */
 #define CONFIG_SYS_MALLOC_LEN		(512 * 1024) /* Reserved for malloc */
 
 /*