move irqhandler to application

tud_isr() must be called by application to forward the irqhandle to the
stack

examples/device/board_test/Makefile

@@ -9,4 +9,10 @@ INC += \
 EXAMPLE_SOURCE += $(wildcard src/*.c)
 SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
 
+# board_test example is special example that doesn't enable device or host stack
+# This can cause some TinyUSB API missing, this hack to allow us to fill those API
+# to pass the compilation process
+CFLAGS +=	\
+	-D"tud_isr(x)= " \
+
 include ../../rules.mk