crypto: crct10dif - remove from crypto API

Remove the "crct10dif" shash algorithm from the crypto API.  It has no
known user now that the lib is no longer built on top of it.  It has no
remaining references in kernel code.  The only other potential users
would be the usual components that allow specifying arbitrary hash
algorithms by name, namely AF_ALG and dm-integrity.   However there are
no indications that "crct10dif" is being used with these components.
Debian Code Search and web searches don't find anything relevant, and
explicitly grepping the source code of the usual suspects (cryptsetup,
libell, iwd) finds no matches either.  "crc32" and "crc32c" are used in
a few more places, but that doesn't seem to be the case for "crct10dif".

crc_t10dif_update() is also tested by crc_kunit now, so the test
coverage provided via the crypto self-tests is no longer needed.

Also note that the "crct10dif" shash algorithm was inconsistent with the
rest of the shash API in that it wrote the digest in CPU endianness,
making the resulting byte array differ on little endian vs. big endian
platforms.  This means it was effectively just built for use by the lib
functions, and it was not actually correct to treat it as "just another
hash function" that could be dropped in via the shash API.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250206173857.39794-1-ebiggers@kernel.org


Signed-off-by: Eric Biggers <ebiggers@google.com>