rxrpc: Remove call->state_lock

jira LE-1907
Rebuild_History Non-Buildable kernel-rt-5.14.0-284.30.1.rt14.315.el9_2
commit-author David Howells <dhowells@redhat.com>
commit 96b4059
Empty-Commit: Cherry-Pick Conflicts during history rebuild.
Will be included in final tarball splat. Ref for failed cherry-pick at:
ciq/ciq_backports/kernel-rt-5.14.0-284.30.1.rt14.315.el9_2/96b4059f.failed

All the setters of call->state are now in the I/O thread and thus the state
lock is now unnecessary.

	Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
(cherry picked from commit 96b4059)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>

# Conflicts:
#	net/rxrpc/ar-internal.h
#	net/rxrpc/call_accept.c
#	net/rxrpc/call_event.c
#	net/rxrpc/call_object.c
#	net/rxrpc/call_state.c
#	net/rxrpc/conn_client.c
#	net/rxrpc/conn_event.c
#	net/rxrpc/input.c
#	net/rxrpc/output.c
#	net/rxrpc/rxkad.c
#	net/rxrpc/sendmsg.c

Author: PlaidCat