Disable DEVICE_STDIO_MESSAGES for LPC81X

Because the LPC81X HAL implementation calls error(), which in turn calls
fprintf(), quite a bit of code is added to the image, which is not a good
idea on such resource constrained targets.

Author: bogdanm

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC81X/TARGET_LPC81X_COMMON/device.h

@@ -48,7 +48,7 @@
 
 #define DEVICE_DEBUG_AWARENESS  0
 
-#define DEVICE_STDIO_MESSAGES   1
+#define DEVICE_STDIO_MESSAGES   0
 
 #define DEVICE_ERROR_RED        1