Deprecate std::filesystem namespace include

Clang-tidy is complaining about our using fs = ... directives.  These
were originally added to handle boost::filesystem vs
std::experimental::filesystem vs std::filesystem between the various
compilers.  Now that we're all on std::filesystem, this redefinition can
be removed.

```
ChassisIntrusionSensor.hpp:11:11: error: namespace alias decl 'fs' is unused [misc-unused-alias-decls,-warnings-as-errors]
   11 | namespace fs = std::filesystem;
```

Tested: code compiles

Change-Id: If4b968ff9cceb4038f526321d3c7c11563ffbce9
Signed-off-by: Ed Tanous <etanous@nvidia.com>
diff --git a/src/hwmon-temp/HwmonTempMain.cpp b/src/hwmon-temp/HwmonTempMain.cpp
index f7ccb4f..a9ec2c1 100644
--- a/src/hwmon-temp/HwmonTempMain.cpp
+++ b/src/hwmon-temp/HwmonTempMain.cpp
@@ -62,8 +62,6 @@
 static constexpr double maxValueTemperature = 127;      // DegreesC
 static constexpr double minValueTemperature = -128;     // DegreesC
 
-namespace fs = std::filesystem;
-
 static const I2CDeviceTypeMap sensorTypes{
     {"ADM1021", I2CDeviceType{"adm1021", true}},
     {"DPS310", I2CDeviceType{"dps310", false}},
@@ -293,12 +291,13 @@
             // Other IIO devices look like this on sysfs:
             //     /sys/bus/iio/devices/iio:device1/in_temp_input
             //     /sys/bus/iio/devices/iio:device1/in_pressure_input
-            std::vector<fs::path> paths;
-            fs::path root("/sys/bus/iio/devices");
+            std::vector<std::filesystem::path> paths;
+            std::filesystem::path root("/sys/bus/iio/devices");
             findFiles(root, R"(in_temp\d*_(input|raw))", paths);
             findFiles(root, R"(in_pressure\d*_(input|raw))", paths);
             findFiles(root, R"(in_humidityrelative\d*_(input|raw))", paths);
-            findFiles(fs::path("/sys/class/hwmon"), R"(temp\d+_input)", paths);
+            findFiles(std::filesystem::path("/sys/class/hwmon"),
+                      R"(temp\d+_input)", paths);
 
             // iterate through all found temp and pressure sensors,
             // and try to match them with configuration
@@ -307,13 +306,13 @@
                 std::smatch match;
                 const std::string pathStr = path.string();
                 auto directory = path.parent_path();
-                fs::path device;
+                std::filesystem::path device;
 
                 std::string deviceName;
                 std::error_code ec;
                 if (pathStr.starts_with("/sys/bus/iio/devices"))
                 {
-                    device = fs::canonical(directory, ec);
+                    device = std::filesystem::canonical(directory, ec);
                     if (ec)
                     {
                         std::cerr << "Fail to find device in path [" << pathStr
@@ -324,7 +323,8 @@
                 }
                 else
                 {
-                    device = fs::canonical(directory / "device", ec);
+                    device =
+                        std::filesystem::canonical(directory / "device", ec);
                     if (ec)
                     {
                         std::cerr << "Fail to find device in path [" << pathStr