thermal/drivers/mediatek/lvts_thermal: Remove redundant msg in lvts_ctrl_start()

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

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230620090732.50025-10-frank.li@vivo.com