New comment by tornaria on void-packages repository

https://github.com/void-linux/void-packages/pull/32641#issuecomment-904191567

Comment:
From #32638:
> > XBPS_USE_BUILD_MTIME=no
> 
> I don't think it's good style to poke at such bits. It's not xbps-src "API".

I removed it. No other changes.