ARM label operands can be quoted.

For example, labels from Objective-C sources.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143511 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 757eccb..0abfabe 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -3810,6 +3810,7 @@
   }
   case AsmToken::LParen:  // parenthesized expressions like (_strcmp-4)
   case AsmToken::Integer: // things like 1f and 2b as a branch targets
+  case AsmToken::String:  // quoted label names.
   case AsmToken::Dot: {   // . as a branch target
     // This was not a register so parse other operands that start with an
     // identifier (like labels) as expressions and create them as immediates.