add tinyusb

tinyusb/hw/bsp/stm32f7/boards/stlinkv3mini/board.mk

@@ -0,0 +1,14 @@
+# Only OTG-HS has a connector on this board
+PORT ?= 1
+SPEED ?= high
+
+CFLAGS += \
+  -DSTM32F723xx \
+  -DHSE_VALUE=25000000 \
+
+# All source paths should be relative to the top level.
+LD_FILE = $(BOARD_PATH)/STM32F723xE_FLASH.ld
+SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32f723xx.s
+
+# flash target using on-board stlink
+flash: flash-stlink