dt: thermal: tsens: Document compatible for MSM8976/56

Support for MSM8976 and MSM8956 (having tsens ip version 1) has
been added to the qcom tsens driver: document the addition here.

Signed-off-by: AngeloGioacchino Del Regno <kholk11@gmail.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191005104133.30297-3-kholk11@gmail.com