[WebAssembly] Fixed disassembler not knowing about new brlist operand

Summary:
The previously introduced new operand type for br_table didn't have
a disassembler implementation, causing an assert.

Reviewers: dschuff, aheejin

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D56227

llvm-svn: 350366
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
index a111eb5..a01517f 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
@@ -79,6 +79,8 @@
   OPERAND_TYPEINDEX,
   /// Event index.
   OPERAND_EVENT,
+  /// A list of branch targets for br_list.
+  OPERAND_BRLIST,
 };
 } // end namespace WebAssembly