Cleanup old headers and namespace declarations

Remove the header includes for the old phosphor::logging::log API
as well as unnecessary phosphor::logging namespace declarations.
Fully qualify phosphor::logging namespace where applicable and/or
needed.

Tested:
* Verified commit passed CI unit tests.
* Verified commit built using bitbake.

Change-Id: I2e490e1aa3fd3423f8c52694c2b97bc58b95525a
Signed-off-by: Anwaar Hadi <anwaar.hadi@ibm.com>
diff --git a/utility.hpp b/utility.hpp
index a55a52f..c37df98 100644
--- a/utility.hpp
+++ b/utility.hpp
@@ -9,7 +9,6 @@
 #include <sdbusplus/bus.hpp>
 #include <xyz/openbmc_project/Common/error.hpp>
 
-using namespace phosphor::logging;
 using InternalFailure =
     sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure;
 
@@ -66,7 +65,7 @@
         {
             lg2::error("Failed to open file device path {PATH}", "PATH",
                        pathname);
-            elog<InternalFailure>();
+            phosphor::logging::elog<InternalFailure>();
         }
     }