uboot-phytec

configs: socfpga: mcvevk: Remove useless UBI infos

There is no flash on this board, there is no reason to define MTD
environment variables nor UBI. Drop them from the configuration file.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Wolfgang Grandegger <wg@aries-embedded.de>