meson: remove cppfs dependency and experimental::filesystem

The dependency on the c++fs library is something very old from the C++14
era and is no longer necessary with a modern compiler.  Remove the
explicit dependency from the meson setup.

Remove all use of `std::experimental::filesystem` and replace with the
real `std::filesystem`.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I62214337ec1b72f7c999de605b9ebe409d22ce79
diff --git a/presence/gpio_presence.hpp b/presence/gpio_presence.hpp
index b72e84e..b6ea47a 100644
--- a/presence/gpio_presence.hpp
+++ b/presence/gpio_presence.hpp
@@ -6,7 +6,7 @@
 #include <sdbusplus/bus.hpp>
 
 #include <cstdlib>
-#include <experimental/filesystem>
+#include <filesystem>
 #include <string>
 
 namespace phosphor
@@ -19,7 +19,7 @@
 static constexpr auto deviceField = 0;
 static constexpr auto pathField = 1;
 using Device = std::string;
-using Path = std::experimental::filesystem::path;
+using Path = std::filesystem::path;
 using Driver = std::tuple<Device, Path>;
 using Interface = std::string;
 
diff --git a/presence/meson.build b/presence/meson.build
index 1476e24..c46f844 100644
--- a/presence/meson.build
+++ b/presence/meson.build
@@ -4,7 +4,6 @@
     'main.cpp',
     'gpio_presence.cpp',
     dependencies: [
-        cppfs,
         libevdev,
         phosphor_logging,
     ],