thermal/drivers/ti-soc-thermal: Avoid dereferencing ERR_PTR

On error the function ti_bandgap_get_sensor_data() returns the error
code in ERR_PTR() but we only checked if the return value is NULL or
not. And, so we can dereference an error code inside ERR_PTR.
While at it, convert a check to IS_ERR_OR_NULL.

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200424161944.6044-1-sudipm.mukherjee@gmail.com

drivers/thermal/ti-soc-thermal/ti-thermal-common.c

@@ -169,7 +169,7 @@ int ti_thermal_expose_sensor(struct ti_bandgap *bgp, int id,
 
 	data = ti_bandgap_get_sensor_data(bgp, id);
 
-	if (!data || IS_ERR(data))
+	if (!IS_ERR_OR_NULL(data))
 		data = ti_thermal_build_data(bgp, id);
 
 	if (!data)
@@ -196,7 +196,7 @@ int ti_thermal_remove_sensor(struct ti_bandgap *bgp, int id)
 
 	data = ti_bandgap_get_sensor_data(bgp, id);
 
-	if (data && data->ti_thermal) {
+	if (!IS_ERR_OR_NULL(data) && data->ti_thermal) {
 		if (data->our_zone)
 			thermal_zone_device_unregister(data->ti_thermal);
 	}
@@ -262,7 +262,7 @@ int ti_thermal_unregister_cpu_cooling(struct ti_bandgap *bgp, int id)
 
 	data = ti_bandgap_get_sensor_data(bgp, id);
 
-	if (data) {
+	if (!IS_ERR_OR_NULL(data)) {
 		cpufreq_cooling_unregister(data->cool_dev);
 		if (data->policy)
 			cpufreq_cpu_put(data->policy);