hwmon: (coretemp) Avoid leaving around dangling pointer

Storing the struct temp_data pointer allocated from create_core_data()
when returning an error has the potential of leaving around a pointer
to freed memory. Reset it to NULL for error returns.

Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index cf5b1de..9323837 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -506,6 +506,7 @@
 
 	return 0;
 exit_free:
+	pdata->core_data[attr_no] = NULL;
 	kfree(tdata);
 	return err;
 }