rxrpc: Don't set the MORE-PACKETS rxrpc wire header flag

rxrpc: Don't set the MORE-PACKETS rxrpc wire header flag

The MORE-PACKETS rxrpc header flag hasn't actually been looked at by
anything since 1988 and not all implementations generate it.

Change rxrpc so that it doesn't set MORE-PACKETS at all rather than setting
it inconsistently.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20241204074710.990092-6-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>