thermal/drivers/sun8i: Remove redundant msg in sun8i_ths_register()

The upper-layer devm_thermal_add_hwmon_sysfs() function can directly
print error information.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230620090732.50025-2-frank.li@vivo.com