powerpc/mpc83xx: increment malloc heap size

extention of commit 3b6b256 "powerpc/mpc83xx: increment
malloc heap size for the MPC832x MDS boards" to all other
mpc83xx based boards.  It fixes "Unable to save the rest
of sector" messages when trying to save the environment
to flash.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
diff --git a/include/configs/MPC8323ERDB.h b/include/configs/MPC8323ERDB.h
index ddee1ae..8c027f9 100644
--- a/include/configs/MPC8323ERDB.h
+++ b/include/configs/MPC8323ERDB.h
@@ -156,7 +156,7 @@
 
 /* CONFIG_SYS_MONITOR_LEN must be a multiple of CONFIG_ENV_SECT_SIZE */
 #define CONFIG_SYS_MONITOR_LEN	(384 * 1024)	/* Reserve 384 kB for Mon */
-#define CONFIG_SYS_MALLOC_LEN	(128 * 1024)	/* Reserved for malloc */
+#define CONFIG_SYS_MALLOC_LEN	(256 * 1024)	/* Reserved for malloc */
 
 /*
  * Initial RAM Base Address Setup