spl: net: dm: usb: bind the gadget before attempting to load the image

If DM_USB_GADGET is used, the usb ethernet gadget driver must be bound to a
controller before the image can be downloaded over the network.
In u-boot this can be done with the bind command. In SPL it must be done
programmatically.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/spl_net.c b/common/spl/spl_net.c
index b6967ff..c91ad2b 100644
--- a/common/spl/spl_net.c
+++ b/common/spl/spl_net.c
@@ -85,7 +85,9 @@
 			   struct spl_boot_device *bootdev)
 {
 	bootdev->boot_device_name = "usb_ether";
-
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
+	usb_ether_init();
+#endif
 	return spl_net_load_image(spl_image, bootdev);
 }
 SPL_LOAD_IMAGE_METHOD("USB eth", 0, BOOT_DEVICE_USBETH, spl_net_load_image_usb);