Fix off-by-one buffer error

The _GET_CPU macro will write a terminating zero at cpu[8].

Detected by cppcheck

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30749 a1c6a512-1295-4272-9138-f99709370657

utils/jz4740_tools/jz4740_usbtool.c

@@ -420,8 +420,8 @@ int mimic_of(usb_dev_handle *dh, bool vx767)
 {
     int err, fsize;
     unsigned char *buffer, *buffer2;
-    char cpu[8];
-    
+    char cpu[9];
+
     fprintf(stderr, "[INFO] Start!\n");
     _GET_CPU;
     _SET_ADDR(0x8000 << 16);