arm: kirkwood: openrd: Remove superfluous CONFIG_ENV_ADDR

Remove the superfluous CONFIG_ENV_ADDR definition. Its not needed
as CONFIG_ENV_OFFSET is also set to the same value.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>