rxrpc: Pull out certain app callback funcs into an ops table

A number of functions separately furnish an AF_RXRPC socket with callback
function pointers into a kernel app (such as the AFS filesystem) that is
using it.  Replace most of these with an ops table for the entire socket.
This makes it easier to add more callback functions.

Note that the call incoming data processing callback is retaind as that
gets set to different things, depending on the type of op.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-3-dhowells@redhat.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>