uboot-imx

rockchip: Add PXE and DHCP to the default boot targets

Now that at least on the firefly board we have network support, enable
PXE and DHCP boot targets by default.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Acked-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>