tinyusb: Set CFG_TUSB_MCU for STM32F7

TinyUSB requires definition of CFG_TUSB_MCU.
For STM32F7 it was not defined at all.

Now it is defined and targets for STM32F7 with USB enabled
can be used.
diff --git a/hw/usb/tinyusb/synopsys/include/tusb_hw.h b/hw/usb/tinyusb/synopsys/include/tusb_hw.h
index 34471fd..885671d 100755
--- a/hw/usb/tinyusb/synopsys/include/tusb_hw.h
+++ b/hw/usb/tinyusb/synopsys/include/tusb_hw.h
@@ -24,6 +24,8 @@
 
 #if MYNEWT_VAL(MCU_STM32F4)
 #define CFG_TUSB_MCU OPT_MCU_STM32F4
+#elif MYNEWT_VAL(MCU_STM32F7)
+#define CFG_TUSB_MCU OPT_MCU_STM32F7
 #elif MYNEWT_VAL(MCU_STM32L4)
 #define CFG_TUSB_MCU OPT_MCU_STM32L4
 #endif