[RISCV] Fix double counting scalar CSRs with Zcmp when emitting cfi_offset for RVV CSRs. (llvm#117408)

getCalleeSavedStackSize() already contains RVPushStackSize. Don't
subtract it again.

Author: topperc

llvm/lib/Target/RISCV/RISCVFrameLowering.cpp

@@ -1658,8 +1658,7 @@ void RISCVFrameLowering::emitCalleeSavedRVVPrologCFI(
   if (!HasFP) {
     uint64_t ScalarLocalVarSize =
         MFI.getStackSize() - RVFI->getCalleeSavedStackSize() -
-        RVFI->getRVPushStackSize() - RVFI->getVarArgsSaveSize() +
-        RVFI->getRVVPadding();
+        RVFI->getVarArgsSaveSize() + RVFI->getRVVPadding();
     FixedSize -= ScalarLocalVarSize;
   }