physical: Fix cppcoreguidelines-explicit-virtual-functions
```
/home/andrew/src/openbmc/phosphor-led-sysfs/build/../physical.hpp:32:5: error: annotate this function with 'override' or (rarely) 'final' [cppcoreguidelines-explicit-virtual-functions,modernize-use-override,-warnings-as-errors]
~Physical() = default;
^
override
```
Change-Id: I0f631ec59c8b3035f085fe475465d4fb09183632
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/physical.hpp b/physical.hpp
index 3592494..885bf55 100644
--- a/physical.hpp
+++ b/physical.hpp
@@ -29,7 +29,7 @@
{
public:
Physical() = delete;
- ~Physical() = default;
+ ~Physical() override = default;
Physical(const Physical&) = delete;
Physical& operator=(const Physical&) = delete;
Physical(Physical&&) = delete;