Write the clang-tidy file OpenBMC needs

Now that CI can handle clang-tidy, and a lot of the individual fixes
have landed for the various static analysis checks, lets see how close
we are.

This includes bringing a bunch of the code up to par with the checks
that require.  Most of them fall into the category of extraneous else
statements, const correctness problems, or extra copies.

Tested:
CI only.  Unit tests pass.

Signed-off-by: Ed Tanous <ed@tanous.net>
Change-Id: I9fbd346560a75fdd3901fa40c57932486275e912
diff --git a/redfish-core/lib/pcie.hpp b/redfish-core/lib/pcie.hpp
index 21ec6dc..19438af 100644
--- a/redfish-core/lib/pcie.hpp
+++ b/redfish-core/lib/pcie.hpp
@@ -45,7 +45,7 @@
         pcieDeviceList = nlohmann::json::array();
         for (const std::string& pcieDevicePath : pcieDevicePaths)
         {
-            size_t devStart = pcieDevicePath.rfind("/");
+            size_t devStart = pcieDevicePath.rfind('/');
             if (devStart == std::string::npos)
             {
                 continue;