hwmon: (w83795) temp4_type has writable permission

Both datasheet and comments of store_temp_mode() tell us that temp1~4_type
is writable, so fix it.

Signed-off-by: Yao Wang <wangyao@lemote.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Fixes: 39deb699 (" hwmon: (w83795) Simplify temperature sensor type handling")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>