[Target] Remove unused forward declarations (NFC)

GitOrigin-RevId: d0ec61c9ffb32891ed02e57fd2327aa4d641ecde
diff --git a/lib/Target/AArch64/AArch64FrameLowering.h b/lib/Target/AArch64/AArch64FrameLowering.h
index f59860a..2d9c346 100644
--- a/lib/Target/AArch64/AArch64FrameLowering.h
+++ b/lib/Target/AArch64/AArch64FrameLowering.h
@@ -18,8 +18,6 @@
 
 namespace llvm {
 
-class MCCFIInstruction;
-
 class AArch64FrameLowering : public TargetFrameLowering {
 public:
   explicit AArch64FrameLowering()
diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h b/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h
index 7d1de3e..049c497 100644
--- a/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h
@@ -33,7 +33,6 @@
 class MCTargetOptions;
 class MCTargetStreamer;
 class Target;
-class FeatureBitset;
 
 MCCodeEmitter *createAArch64MCCodeEmitter(const MCInstrInfo &MCII,
                                           MCContext &Ctx);
diff --git a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCCodeEmitter.h b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCCodeEmitter.h
index 228963f..200c9b8 100644
--- a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCCodeEmitter.h
+++ b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCCodeEmitter.h
@@ -23,7 +23,6 @@
 class MCInstrInfo;
 class MCOperand;
 class MCSubtargetInfo;
-class FeatureBitset;
 
 class AMDGPUMCCodeEmitter : public MCCodeEmitter {
   virtual void anchor();
diff --git a/lib/Target/AMDGPU/MCTargetDesc/R600MCTargetDesc.h b/lib/Target/AMDGPU/MCTargetDesc/R600MCTargetDesc.h
index b4ce748..cf40e7e 100644
--- a/lib/Target/AMDGPU/MCTargetDesc/R600MCTargetDesc.h
+++ b/lib/Target/AMDGPU/MCTargetDesc/R600MCTargetDesc.h
@@ -21,7 +21,6 @@
 class MCCodeEmitter;
 class MCContext;
 class MCInstrInfo;
-class MCRegisterInfo;
 
 MCCodeEmitter *createR600MCCodeEmitter(const MCInstrInfo &MCII,
                                        MCContext &Ctx);
diff --git a/lib/Target/AMDGPU/SIInstrInfo.cpp b/lib/Target/AMDGPU/SIInstrInfo.cpp
index 8eed1b0..02384e3 100644
--- a/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -39,9 +39,6 @@
 #include "AMDGPUGenInstrInfo.inc"
 
 namespace llvm {
-
-class AAResults;
-
 namespace AMDGPU {
 #define GET_D16ImageDimIntrinsics_IMPL
 #define GET_ImageDimIntrinsicTable_IMPL