[dwarfdump] Fix frame info register number dump.

llvm-svn: 230559
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
index 524d728..7d77290 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
@@ -381,7 +381,7 @@
       OS << format(" %" PRId64 "*data_alignment_factor" , Operand);
     break;
   case OT_Register:
-    OS << format(" reg%d", Operand);
+    OS << format(" reg%" PRId64, Operand);
     break;
   case OT_Expression:
     OS << " expression";