thermal/drivers/rockchip: Shut up GRF warning

thermal/drivers/rockchip: Shut up GRF warning

Most of the recent Rockchip devices do not have a GRF associated
with the tsadc IP. Let's avoid printing a warning on those devices.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Tested-by: Diederik de Haas <didi.debian@cknow.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20250820-thermal-rockchip-grf-warning-v2-2-c7e2d35017b8@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>