[llvm-c][Disassembler] When printing latency information, fall back to the
itinerary model in case the target does not supply a scheduling model.

By doing this, targets like cortex-a8 can benefit from the latency printing
feature added in r191859.

This part of <rdar://problem/14687488>. 

llvm-svn: 191916
diff --git a/llvm/lib/MC/MCDisassembler/Disassembler.h b/llvm/lib/MC/MCDisassembler/Disassembler.h
index 05c92df..4855af2 100644
--- a/llvm/lib/MC/MCDisassembler/Disassembler.h
+++ b/llvm/lib/MC/MCDisassembler/Disassembler.h
@@ -75,6 +75,8 @@
   llvm::OwningPtr<llvm::MCInstPrinter> IP;
   // The options used to set up the disassembler.
   uint64_t Options;
+  // The CPU string.
+  std::string CPU;
 
 public:
   // Comment stream and backing vector.
@@ -119,6 +121,8 @@
   void setIP(MCInstPrinter *NewIP) { IP.reset(NewIP); }
   uint64_t getOptions() const { return Options; }
   void addOptions(uint64_t Options) { this->Options |= Options; }
+  StringRef getCPU() const { return CPU; }
+  void setCPU(const char *CPU) { this->CPU = CPU; }
 };
 
 } // namespace llvm