[lld-macho] Fix IWYU issues. NFC

Author: MaskRay

lld/MachO/Config.h

@@ -12,7 +12,6 @@
 #include "llvm/ADT/CachedHashString.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
-#include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"

lld/MachO/SectionPriorities.h

@@ -11,6 +11,7 @@
 
 #include "InputSection.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/MapVector.h"
 
 namespace lld::macho {
 

lld/MachO/SyntheticSections.h

@@ -19,6 +19,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/BinaryFormat/MachO.h"
 #include "llvm/Support/MathExtras.h"