Map the thermal sensor in the BCM2835 block.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20191019234715.25750-3-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>