GlobalISel: remove unused variable to silence warning.

llvm-svn: 287027
diff --git a/llvm/lib/Target/ARM/ARMInstructionSelector.cpp b/llvm/lib/Target/ARM/ARMInstructionSelector.cpp
index 69b94b6..892b770 100644
--- a/llvm/lib/Target/ARM/ARMInstructionSelector.cpp
+++ b/llvm/lib/Target/ARM/ARMInstructionSelector.cpp
@@ -28,7 +28,7 @@
 ARMInstructionSelector::ARMInstructionSelector(const ARMSubtarget &STI,
                                                const ARMRegisterBankInfo &RBI)
     : InstructionSelector(), TII(*STI.getInstrInfo()),
-      TRI(*STI.getRegisterInfo()), RBI(RBI) {}
+      TRI(*STI.getRegisterInfo()) {}
 
 bool ARMInstructionSelector::select(llvm::MachineInstr &I) const {
   return !isPreISelGenericOpcode(I.getOpcode());