use std::format instead of fmt::format

The std::format is sufficient for the uses in this repository except
for in one file (override_fan_target.cpp, since P2286 isn't supported
by GCC yet).  Switch to std::format whenever possible.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ib2576fb530a4d7ce238e1b0bd95b40b476ec2107
diff --git a/utility.hpp b/utility.hpp
index cbf6205..727b557 100644
--- a/utility.hpp
+++ b/utility.hpp
@@ -1,7 +1,6 @@
 #pragma once
 
 #include <fcntl.h>
-#include <fmt/format.h>
 #include <unistd.h>
 
 #include <phosphor-logging/elog-errors.hpp>
@@ -10,6 +9,8 @@
 #include <sdbusplus/bus.hpp>
 #include <xyz/openbmc_project/Common/error.hpp>
 
+#include <format>
+
 using namespace phosphor::logging;
 using InternalFailure =
     sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure;
@@ -66,7 +67,7 @@
         if (-1 == fd)
         {
             log<level::ERR>(
-                fmt::format("Failed to open file device path {}", pathname)
+                std::format("Failed to open file device path {}", pathname)
                     .c_str());
             elog<InternalFailure>();
         }