Corrected minor license header inconsistency

src/common/file_util.cpp

@@ -4,6 +4,7 @@
 
 // Copyright Dolphin Emulator Project
 // Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
 
 #include <array>
 #include <fstream>

src/common/file_util.h

@@ -6,6 +6,7 @@
 
 // Copyright Dolphin Emulator Project
 // Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
 
 #pragma once