powerpc/mm: Remove empty hash__ functions

The empty hash__* functions are unnecessary. The empty definitions were
introduced when 64-bit Hash support was added, as the functions were
still used in generic code. These empty definitions were prefixed with
hash__ when Radix support was added, and new wrappers with the original
names were added that selected the Radix or Hash version based on
radix_enabled().

But the hash__ prefixed functions were not part of a public interface,
so there is no need to include them for compatibility with anything.
Generic code will use the non-prefixed wrappers, and Hash specific code
will know that there is no point in calling them (or even worse, call
them and expect them to do something).

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221109045112.187069-5-bgray@linux.ibm.com