Don't disassemble symbols with an unknown address or size.

Patch by Nico Rieck!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178678 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index 322bd21..7832cf0 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -228,6 +228,7 @@
       if (!error(i->containsSymbol(*si, contains)) && contains) {
         uint64_t Address;
         if (error(si->getAddress(Address))) break;
+        if (Address == UnknownAddressOrSize) continue;
         Address -= SectionAddr;
 
         StringRef Name;