[ARM] Split Arm jump table branch into i12 and rs suffixed versions

This is a refactoring/cleanup of Arm `addrmode2` operand class. The patch
removes it completely.

Differential Revision: https://reviews.llvm.org/D39832

llvm-svn: 318291
diff --git a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
index e318a86..bc781b2 100644
--- a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -564,7 +564,8 @@
     case ARM::BR_JTadd:
     case ARM::BR_JTr:
     case ARM::tBR_JTr:
-    case ARM::BR_JTm:
+    case ARM::BR_JTm_i12:
+    case ARM::BR_JTm_rs:
       JTOpcode = ARM::JUMPTABLE_ADDRS;
       break;
     case ARM::t2BR_JT: