buildroot insists on BR2_PREFER_SOFT_FLOAT=y

I'm worried about this: even if I set this manually to `n', at the next `make
menuconfig' it reverts to `y'

according to the .config, BR2_SOFT_FLOAT gets its default value from
BR2_PREFER_SOFT_FLOAT, so if that is `y', and BR2_SOFT_FLOAT is not set...

I don't want to build anything with softfp.