Rename sha512 to sha512_generic and add a MODULE_ALIAS for sha512
so all sha512 implementations can be loaded automatically.

Keep the broken tabs so git recognizes this as a rename.
Signed-off-by: NJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>