[PATCH] configs: ls1012a/ls1046a: Define CONFIG_ENV_OVERWRITE

[Kuldeep Singh]

> > Can you please check if this change can go into defconfig file,
> > instead of adding here?
> 
> This will require conversion of CONFIG_ENV_OVERWRITE to Kconfig option
> to add and entry in defconfig.

With little search, I found Adam Ford's patch[1] which convert CONFIG_ENV_OVERWRITE to Kconfig option.
I can make my changes on top of this patch. Please let me know your views.

-Kuldeep
[1] https://patchwork.ozlabs.org/project/uboot/patch/20200703114856.1225522-1-aford173@gmail.com/