phosphor-host-postd: Convert to use bind_front for C++20

Using bind_front instead of bind for better readability and efficient
function binding.

Change-Id: Ia247d00c4b085de96605a07176cd22fbfeac1d55
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/main.cpp b/main.cpp
index 1ccfd21..7ba238c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -25,6 +25,7 @@
 
 #include <cstdint>
 #include <exception>
+#include <functional>
 #include <iostream>
 #include <optional>
 #include <sdeventplus/event.hpp>
@@ -51,8 +52,8 @@
  * Callback handling IO event from the POST code fd. i.e. there is new
  * POST code available to read.
  */
-void PostCodeEventHandler(sdeventplus::source::IO& s, int postFd, uint32_t,
-                          PostReporter* reporter, bool verbose)
+void PostCodeEventHandler(PostReporter* reporter, bool verbose,
+                          sdeventplus::source::IO& s, int postFd, uint32_t)
 {
     uint64_t code = 0;
     ssize_t readb;
@@ -180,9 +181,7 @@
         {
             reporterSource.emplace(
                 event, postFd, EPOLLIN | EPOLLET,
-                std::bind(PostCodeEventHandler, std::placeholders::_1,
-                          std::placeholders::_2, std::placeholders::_3,
-                          &reporter, verbose));
+                std::bind_front(PostCodeEventHandler, &reporter, verbose));
         }
         // Enable bus to handle incoming IO and bus events
         bus.attach_event(event.get(), SD_EVENT_PRIORITY_NORMAL);