microblaze: Short size of global data and fix malloc size

If is full malloc area global, data are rewrite because
there was bad size of malloc area.

Signed-off-by: Michal Simek <monstr@monstr.eu>

include/configs/microblaze-generic.h

@@ -136,13 +136,13 @@
 #define	CONFIG_SYS_MEMTEST_END		(CONFIG_SYS_SDRAM_BASE + 0x1000)
 
 /* global pointer */
-#define	CONFIG_SYS_GBL_DATA_SIZE	0x1000	/* size of global data */
+#define	CONFIG_SYS_GBL_DATA_SIZE	128 /* size of global data */
 /* start of global data */
 #define	CONFIG_SYS_GBL_DATA_OFFSET	(CONFIG_SYS_SDRAM_BASE + CONFIG_SYS_SDRAM_SIZE - CONFIG_SYS_GBL_DATA_SIZE)
 
 /* monitor code */
 #define	SIZE			0x40000
-#define	CONFIG_SYS_MONITOR_LEN		SIZE
+#define	CONFIG_SYS_MONITOR_LEN		(SIZE - CONFIG_SYS_GBL_DATA_SIZE)
 #define	CONFIG_SYS_MONITOR_BASE	(CONFIG_SYS_GBL_DATA_OFFSET - CONFIG_SYS_MONITOR_LEN)
 #define	CONFIG_SYS_MONITOR_END		(CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN)
 #define	CONFIG_SYS_MALLOC_LEN		SIZE