bdinfo: net: ppc: Drop prints for CONFIG_HAS_ETHn

These config options have not been migrated to Kconfig. This should be
handled using driver model, iterating over the available Ethernet devices.
For now, remove the code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>