thermal/drivers/ti-soc-thermal: Use helper function IS_ERR_OR_NULL()

Use IS_ERR_OR_NULL() to detect an error pointer or a null pointer
open-coding to simplify the code.
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230817014900.3094512-1-lizetao1@huawei.com

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

@@ -314,7 +314,7 @@ int ti_bandgap_adc_to_mcelsius(struct ti_bandgap *bgp, int adc_val, int *t)
  */
 static inline int ti_bandgap_validate(struct ti_bandgap *bgp, int id)
 {
-	if (!bgp || IS_ERR(bgp)) {
+	if (IS_ERR_OR_NULL(bgp)) {
 		pr_err("%s: invalid bandgap pointer\n", __func__);
 		return -EINVAL;
 	}