While upstreaming the RISC-V port, it was pointed out that multiple architectures have copied the mostly empty versions of at least one of these functions. This defines weakly bound versions of the common functions and removes the now obselete functions from other ports. This has been split out from the RISC-V submission so we can decouple all these generic changes from our port review process. There's some discussion on an earlier version of the patch here https://lkml.org/lkml/2017/6/6/998 but I'm afraid a lot of this is really out of my wheelhouse (and I'm pretty slammed trying to get the RISC-V port in better shape), so I'm afraid I'm not going to be able to perform the full cleanup suggested.
