sunxi: add NetConsole by default for Banana Pi/Pro

sunxi: add NetConsole by default for Banana Pi/Pro

Simon Glass and Joe Hershberger suggested adding at least one
test case for the CONFIG_DM_ETH plus CONFIG_NETCONSOLE options.

This patch enables NetConsole as a default for the "Banana Pi/Pro"
sunxi boards.

(By the nature of this patch it could probably be extended later
to include all sunxi boards using CONFIG_SUNXI_[EG]MAC.)

Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>