Revert "accel/tcg: Unregister the RCU before exiting RR thread"

Revert "accel/tcg: Unregister the RCU before exiting RR thread"

This reverts commit bc93332fe460211c2d2f4ff50e1a0e030c7b5159,
which was merged prematurely, re-introducing Coverity CID 1547782
(unreachable code).

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250715104015.72663-2-philmd@linaro.org>