add TUSB_CFG_HOST_ENUM_BUFFER_SIZE

add enum buffer
getting serious with osal_freeRTOS

tests/test/support/FreeRTOS/readme.txt

@@ -0,0 +1,21 @@
+Directories:
+
++ The FreeRTOS/Source directory contains the FreeRTOS source code, and contains
+  its own readme file.
+
++ The FreeRTOS/Demo directory contains a demo application for every official
+FreeRTOS port, and contains its own readme file.
+
++ See http://www.freertos.org/a00017.html for full details of the directory 
+  structure and information on locating the files you require.
+
+The easiest way to use FreeRTOS is to start with one of the pre-configured demo 
+application projects (found in the FreeRTOS/Demo directory).  That way you will
+have the correct FreeRTOS source files included, and the correct include paths
+configured.  Once a demo application is building and executing you can remove
+the demo application file, and start to add in your own application source
+files.
+
+See also -
+http://www.freertos.org/FreeRTOS-quick-start-guide.html
+http://www.freertos.org/FAQHelp.html