misc: tsl2550: replace simple_strtoul to kstrtoul

The function simple_strtoul performs no error checking
in scenarios where the input value overflows the intended
output variable.

We can replace the use of the simple_strtoul with the safer
alternatives kstrtoul.

Signed-off-by: Hongbo Li <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/tsl2550.c

···
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct tsl2550_data *data = i2c_get_clientdata(client);
-	unsigned long val = simple_strtoul(buf, NULL, 10);
+	unsigned long val;
 	int ret;
 
-	if (val > 1)
+	if (kstrtoul(buf, 10, &val) || val > 1)
 		return -EINVAL;
 
 	mutex_lock(&data->update_lock);
···
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct tsl2550_data *data = i2c_get_clientdata(client);
-	unsigned long val = simple_strtoul(buf, NULL, 10);
+	unsigned long val;
 	int ret;
 
-	if (val > 1)
+	if (kstrtoul(buf, 10, &val) || val > 1)
 		return -EINVAL;
 
 	if (data->power_state == 0)