The PL031 is a Real Time Clock, not a timer.
Move it under the hw/rtc/ subdirectory.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20191003230404.19384-3-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>