Move various generated tables into read-only memory, fixing up const correctness along the way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142726 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index dcdb452..1517625 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -415,7 +415,7 @@
 }
 
 namespace llvm {
-extern MCInstrDesc ARMInsts[];
+extern const MCInstrDesc ARMInsts[];
 }
 
 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the