thermal: imx: handle error path in one place to save duplicated code

During probe phase, the error path can be handled in one place and
use goto method to save many duplicated code.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>