hwmon: (tmp102) Use device_property_read_string API

hwmon: (tmp102) Use device_property_read_string API

Replace of_property_read_string() with the preferded
device_property_read_string() in the probe function to
read the device label property, improving the driver
compatibility since this method is not limited to
Device Tree only.

Also drop the now unnecessary __maybe_unused from tmp102_of_match.

Signed-off-by: Flaviu Nistor <flaviu.nistor@gmail.com>
Link: https://lore.kernel.org/r/20260510092543.12352-1-flaviu.nistor@gmail.com
Link: https://lore.kernel.org/r/20260518122210.10288-1-flaviu.nistor@gmail.com
[groeck: Combined API change with __maybe_unused patch]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>