generic-adc-battery: Fix checking if none of the channels are supported

If none of the channels are supported, index is 0. Also ensure to return
error code instead of 0 in goto second_mem_fail path.

Signed-off-by: Axel Lin <[e-mail]>
Acked-by: anish kumar <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

drivers/power/generic-adc-battery.c

···
 	}
 
 	/* none of the channels are supported so let's bail out */
-	if (index == ARRAY_SIZE(gab_chan_name))
+	if (index == 0) {
+		ret = -ENODEV;
 		goto second_mem_fail;
+	}
 
 	/*
 	 * Total number of properties is equal to static properties