hw/sensor/tmp105: OS (one-shot) bit in config register always returns 0

hw/sensor/tmp105: OS (one-shot) bit in config register always returns 0

Per datasheet, "ONE-SHOT (OS)", the OS bit always returns 0 when reading
the configuration register.

Clear the ONE_SHOT bit in the WRITE path. Now than the READ path is
simpler, we can also simplify tmp105_alarm_update().

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20240906154911.86803-5-philmd@linaro.org>