Merge branch 'consolidate-fcrypt-and-pcbc-code-into-net-rxrpc'

Eric Biggers says:

====================
Consolidate FCrypt and PCBC code into net/rxrpc/

The FCrypt "block cipher" and the PCBC mode of operation are obsolete
and insecure.  Since their only user is net/rxrpc/, they belong there,
not in the crypto API.

Therefore, this series removes these algorithms from the crypto API and
replaces them with local implementations in net/rxrpc/.

The local implementations are simpler too, as they avoid the crypto API
boilerplate.

I don't know how to test all the code in net/rxrpc/, but everything
should still work.  I added a KUnit test for the crypto functions.
====================

Link: https://patch.msgid.link/20260522050740.84561-1-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>