[ARM] Remove unused includes (NFC)

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

Author: kazutakahirata

llvm/lib/Target/ARM/ARMFixCortexA57AES1742098Pass.cpp

@@ -52,9 +52,7 @@
 #include "llvm/CodeGen/Register.h"
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/IR/DebugLoc.h"
-#include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
-#include "llvm/PassRegistry.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include <assert.h>

llvm/lib/Target/ARM/ARMFrameLowering.cpp

@@ -133,7 +133,6 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
-#include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/Attributes.h"

llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp

@@ -55,7 +55,6 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/SubtargetFeature.h"
 #include "llvm/TargetParser/TargetParser.h"
-#include "llvm/TargetParser/Triple.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>

llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp

@@ -20,7 +20,6 @@
 #include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCContext.h"
-#include "llvm/MC/MCDirectives.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCFixupKindInfo.h"

llvm/lib/Target/ARM/Thumb1FrameLowering.cpp

@@ -32,7 +32,6 @@
 #include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
-#include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/DebugLoc.h"
 #include "llvm/Support/Compiler.h"