[AVR] Remove unnecessary casts (NFC) (#155791)

getSubtargetImpl() already returns const AVRSubtarget *.

Author: kazutakahirata

llvm/lib/Target/AVR/AVRAsmPrinter.cpp

@@ -245,7 +245,7 @@ void AVRAsmPrinter::emitXXStructor(const DataLayout &DL, const Constant *CV) {
 bool AVRAsmPrinter::doFinalization(Module &M) {
   const TargetLoweringObjectFile &TLOF = getObjFileLowering();
   const AVRTargetMachine &TM = (const AVRTargetMachine &)MMI->getTarget();
-  const AVRSubtarget *SubTM = (const AVRSubtarget *)TM.getSubtargetImpl();
+  const AVRSubtarget *SubTM = TM.getSubtargetImpl();
 
   bool NeedsCopyData = false;
   bool NeedsClearBSS = false;
@@ -294,7 +294,7 @@ bool AVRAsmPrinter::doFinalization(Module &M) {
 
 void AVRAsmPrinter::emitStartOfAsmFile(Module &M) {
   const AVRTargetMachine &TM = (const AVRTargetMachine &)MMI->getTarget();
-  const AVRSubtarget *SubTM = (const AVRSubtarget *)TM.getSubtargetImpl();
+  const AVRSubtarget *SubTM = TM.getSubtargetImpl();
   if (!SubTM)
     return;