uboot-imx

net: sandbox: Share the priv structure with tests

If tests want to implement tx handlers, they will likely need access to
the details in the priv structure.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>