freeRTOS: shrink heap by half

A 128K reservation on a device with 256K of RAM is a bit demanding.
Shrink to fix a link error in a DebugRel build.

Author: P33M

src/FreeRTOSConfig.h

@@ -71,7 +71,7 @@
 /* Memory allocation related definitions. */
 #define configSUPPORT_STATIC_ALLOCATION         0
 #define configSUPPORT_DYNAMIC_ALLOCATION        1
-#define configTOTAL_HEAP_SIZE                   (128*1024)
+#define configTOTAL_HEAP_SIZE                   (64*1024)
 #define configAPPLICATION_ALLOCATED_HEAP        0
 
 /* Hook function related definitions. */