board: toradex: make USB PID from config block optional

If config block support is enabled, USB gadget modes unconditionally
use Toradex Product ID as USB PID. Some applications might prefer a
different and/or static USB PID. Add a Kconfig configuration option
to descide whether to use USB PID from config block or the fallback
config option CONFIG_G_DNL_PRODUCT_NUM.

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
diff --git a/board/toradex/common/tdx-common.c b/board/toradex/common/tdx-common.c
index a3d287e..061abf7 100644
--- a/board/toradex/common/tdx-common.c
+++ b/board/toradex/common/tdx-common.c
@@ -147,7 +147,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_USB_GADGET_DOWNLOAD
+#ifdef CONFIG_TDX_CFG_BLOCK_USB_GADGET_PID
 int g_dnl_bind_fixup(struct usb_device_descriptor *dev, const char *name)
 {
 	unsigned short usb_pid;