thermal: rcar_gen3_thermal: record and check number of TSCs found

Record how many TSCs are found in struct rcar_gen3_thermal_priv, this is
needed to be able to add hardware interrupts for trip points later. Also
add a check to make sure at least one TSC is found.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/rcar_gen3_thermal.c

@@ -75,6 +75,7 @@ struct rcar_gen3_thermal_tsc {
 
 struct rcar_gen3_thermal_priv {
 	struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
+	unsigned int num_tscs;
 };
 
 struct rcar_gen3_thermal_data {
@@ -307,6 +308,13 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 		tsc->zone = zone;
 	}
 
+	priv->num_tscs = i;
+
+	if (!priv->num_tscs) {
+		ret = -ENODEV;
+		goto error_unregister;
+	}
+
 	return 0;
 
 error_unregister: