stm32: Fix mboot build with TinyUSB-enabled boards.

usbd_conf.c unconditionally includes shared/tinyusb/mp_usbd.h which
pulls in tusb.h when MICROPY_HW_ENABLE_USBDEV is set. The
BUILDING_MBOOT guard that disables TinyUSB comes after the include,
so mboot builds fail with missing tusb.h. Guard the include with
!BUILDING_MBOOT.

Also add forward declaration of mp_usbd_ll_init() next to the
MICROPY_HW_TINYUSB_LL_INIT macro in mpconfigboard_common.h, since
the function is used in an inline function in mp_usbd.h but only
declared in the port-specific usbd_conf.h.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

Author: pi-anl

ports/stm32/mpconfigboard_common.h

@@ -262,6 +262,7 @@
 #ifndef MICROPY_HW_ENABLE_USBDEV
 #define MICROPY_HW_ENABLE_USBDEV (1)
 #define MICROPY_HW_TINYUSB_LL_INIT mp_usbd_ll_init
+void mp_usbd_ll_init(void);
 #endif
 
 #ifndef MICROPY_HW_USB_CDC

ports/stm32/usbd_conf.c

@@ -32,7 +32,9 @@
 #include "usbd_core.h"
 #include "py/obj.h"
 #include "py/mphal.h"
+#if !BUILDING_MBOOT
 #include "shared/tinyusb/mp_usbd.h"
+#endif
 #include "irq.h"
 #include "usb.h"