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/sbc8349.h b/include/configs/sbc8349.h
index 7d0dda7..478d0d8 100644
--- a/include/configs/sbc8349.h
+++ b/include/configs/sbc8349.h
@@ -194,7 +194,7 @@
 #define CONFIG_SYS_INIT_SP_OFFSET	CONFIG_SYS_GBL_DATA_OFFSET
 
 #define CONFIG_SYS_MONITOR_LEN	(256 * 1024)	/* Reserve 256 kB for Mon */
-#define CONFIG_SYS_MALLOC_LEN	(128 * 1024)	/* Reserved for malloc */
+#define CONFIG_SYS_MALLOC_LEN	(256 * 1024)	/* Reserved for malloc */
 
 /*
  * Local Bus LCRR and LBCR regs