rxrpc: rxperf: Add test RxGK server keys

Add RxGK server keys of bytes containing { 0, 1, 2, 3, 4, ... } to the
server keyring for the rxperf test server.  This allows the rxperf test
client to connect to it.

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/20250411095303.2316168-15-dhowells@redhat.com


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