configs: sandbox: add USB_ETHER and GADGET_DOWNLOAD gadget support

This is needed for new gadget binding test.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index ea08a9e..4bd0111 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -266,6 +266,10 @@
 CONFIG_USB=y
 CONFIG_USB_EMUL=y
 CONFIG_USB_KEYBOARD=y
+CONFIG_USB_GADGET=y
+CONFIG_USB_GADGET_DOWNLOAD=y
+CONFIG_USB_ETHER=y
+CONFIG_USB_ETH_CDC=y
 CONFIG_DM_VIDEO=y
 CONFIG_VIDEO_COPY=y
 CONFIG_CONSOLE_ROTATION=y