thermal/drivers/rockchip: Use dev_err_probe

Use dev_err_probe to simplify error printing in the driver's probe
routine.

Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230308112253.15659-4-sebastian.reichel@collabora.com