rxrpc: Carry call state out of locked section in rxrpc_rotate_tx_window()

rxrpc: Carry call state out of locked section in rxrpc_rotate_tx_window()

BugLink: https://bugs.launchpad.net/bugs/1836654
[ Upstream commit dfe995224693798e554ab4770f6d8a096afc60cd ]

Carry the call state out of the locked section in rxrpc_rotate_tx_window()
rather than sampling it afterwards.  This is only used to select tracepoint
data, but could have changed by the time we do the tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>