Remove include base/string/stringprintf.h

This is to remove the direct dependency on libchrome.
payload_generator/payload_file.cc had been including the
base/string/stringprintf.h. It already have replaced with std::string,
and then seems no longer needed.

Bug: 360917504
Test: build

Change-Id: Ib877d686678e063657787b51e8c5ccf3d1c3a59d
diff --git a/payload_generator/payload_file.cc b/payload_generator/payload_file.cc
index 8f5b826..a1734c7 100644
--- a/payload_generator/payload_file.cc
+++ b/payload_generator/payload_file.cc
@@ -22,8 +22,6 @@
 #include <map>
 #include <utility>
 
-#include <base/strings/stringprintf.h>
-
 #include "update_engine/common/hash_calculator.h"
 #include "update_engine/common/utils.h"
 #include "update_engine/payload_consumer/file_writer.h"