adding makefile for freertos example

examples/device/cdc_msc_hid_freertos/Makefile

@@ -0,0 +1,26 @@
+include ../../../tools/top.mk
+include ../../make.mk
+
+INC += \
+	src \
+	$(TOP)/hw \
+	$(TOP)/lib/FreeRTOS/Source/include \
+	$(TOP)/lib/FreeRTOS/Source/portable/GCC/$(FREERTOS_PORT)
+	
+# Example source
+EXAMPLE_SOURCE += $(wildcard src/*.c)
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+# Board source
+SRC_C += hw/bsp/$(BOARD)/board_$(BOARD).c
+
+# FreeRTOS source
+SRC_C += \
+	lib/FreeRTOS/Source/list.c \
+	lib/FreeRTOS/Source/queue.c \
+	lib/FreeRTOS/Source/tasks.c \
+	lib/FreeRTOS/Source/timers.c \
+	lib/FreeRTOS/Source/portable/GCC/$(FREERTOS_PORT)/port.c \
+	lib/FreeRTOS/Source/portable/MemMang/heap_4.c \
+
+include ../../rules.mk