[AMDGPU] Remove feature register-banking

[rampitec]

Summary

Since RegBankReassign pass was removed this feature is not
use for anything.

[foad]

LGTM, thanks!

llvm/lib/Target/AMDGPU/AMDGPU.td

 >;
 
 def FeatureDsSrc2Insts : SubtargetFeature<"ds-src2-insts",
   "HasDsSrc2Insts",
   "true",
   "Has ds_*_src2 instructions"
 >;
 
-def FeatureRegisterBanking : SubtargetFeature<"register-banking",
-  "HasRegisterBanking",
-  "true",
-  "Has register banking"
->;
-
 def FeatureVOP3Literal : SubtargetFeature<"vop3-literal",
   "HasVOP3Literal",
   "true",
   "Can use one literal in VOP3"
 >;
 
 def FeatureNoDataDepHazard : SubtargetFeature<"no-data-dep-hazard",
   "HasNoDataDepHazard",
def FeatureGFX10 : GCNSubtargetFeatureGeneration<"GFX10",
    FeatureFlatAddressSpace,
    FeatureCIInsts, Feature16BitInsts,
    FeatureSMemRealTime, FeatureInv2PiInlineImm,
    FeatureApertureRegs, FeatureGFX9Insts, FeatureGFX10Insts, FeatureVOP3P,
    FeatureMovrel, FeatureFastFMAF32, FeatureDPP, FeatureIntClamp,
    FeatureSDWA, FeatureSDWAOmod, FeatureSDWAScalar, FeatureSDWASdst,
    FeatureFlatInstOffsets, FeatureFlatGlobalInsts, FeatureFlatScratchInsts,
    FeatureAddNoCarryInsts, FeatureFmaMixInsts, FeatureGFX8Insts,
-   FeatureNoSdstCMPX, FeatureVscnt, FeatureRegisterBanking,
+   FeatureNoSdstCMPX, FeatureVscnt,
    FeatureVOP3Literal, FeatureDPP8, FeatureExtendedImageInsts,
    FeatureNoDataDepHazard, FeaturePkFmacF16Inst,
    FeatureGFX10A16, FeatureSMemTimeInst, FeatureFastDenormalF32, FeatureG16,
    FeatureUnalignedBufferAccess, FeatureUnalignedDSAccess
   ]
 >;
 
 class FeatureSet<list<SubtargetFeature> Features_> {

llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp

GCNSubtarget::GCNSubtarget(const Triple &TT, StringRef GPU, StringRef FS,
     HasAtomicFaddInsts(false),
     SupportsSRAMECC(false),
     EnableSRAMECC(false),
     HasNoSdstCMPX(false),
     HasVscnt(false),
     HasGetWaveIdInst(false),
     HasSMemTimeInst(false),
     HasShaderCyclesRegister(false),
-    HasRegisterBanking(false),
     HasVOP3Literal(false),
     HasNoDataDepHazard(false),
     FlatAddressSpace(false),
     FlatInstOffsets(false),
     FlatGlobalInsts(false),
     FlatScratchInsts(false),
     ScalarFlatScratchInsts(false),
     HasArchitectedFlatScratch(false),

llvm/lib/Target/AMDGPU/GCNSubtarget.h

protected:
   // for SRAMECC.
   bool EnableSRAMECC;
 
   bool HasNoSdstCMPX;
   bool HasVscnt;
   bool HasGetWaveIdInst;
   bool HasSMemTimeInst;
   bool HasShaderCyclesRegister;
-  bool HasRegisterBanking;
   bool HasVOP3Literal;
   bool HasNoDataDepHazard;
   bool FlatAddressSpace;
   bool FlatInstOffsets;
   bool FlatGlobalInsts;
   bool FlatScratchInsts;
   bool ScalarFlatScratchInsts;
   bool HasArchitectedFlatScratch;
public:
   bool hasSMemTimeInst() const {
     return HasSMemTimeInst;
   }
 
   bool hasShaderCyclesRegister() const {
     return HasShaderCyclesRegister;
   }
 
-  bool hasRegisterBanking() const {
-    return HasRegisterBanking;
-  }
-
   bool hasVOP3Literal() const {
     return HasVOP3Literal;
   }
 
   bool hasNoDataDepHazard() const {
     return HasNoDataDepHazard;
   }