Remove the unused SMP instruction set feature option.

The SMP option is currently not used in the ART codebase
(and it rots away).
Single CPU systems that run SMP code should be able to deal
with it nicely (otherwise the CPU has some serious problems).

Test: mma test-art-target && mma test-art-host

Change-Id: Ifaab42b29de1062866a0af7525de2f834a4a5a57
diff --git a/runtime/arch/instruction_set_features.h b/runtime/arch/instruction_set_features.h
index d84bc02..b6c5c71 100644
--- a/runtime/arch/instruction_set_features.h
+++ b/runtime/arch/instruction_set_features.h
@@ -76,11 +76,6 @@
   // Return a string of the form "div,lpae" or "none".
   virtual std::string GetFeatureString() const = 0;
 
-  // Does the instruction set variant require instructions for correctness with SMP?
-  bool IsSmp() const {
-    return smp_;
-  }
-
   // Down cast this ArmInstructionFeatures.
   const ArmInstructionSetFeatures* AsArmInstructionSetFeatures() const;
 
@@ -102,7 +97,7 @@
   virtual ~InstructionSetFeatures() {}
 
  protected:
-  explicit InstructionSetFeatures(bool smp) : smp_(smp) {}
+  InstructionSetFeatures() {}
 
   // Returns true if variant appears in the array variants.
   static bool FindVariantInArray(const char* const variants[], size_t num_variants,
@@ -110,12 +105,10 @@
 
   // Add architecture specific features in sub-classes.
   virtual std::unique_ptr<const InstructionSetFeatures>
-      AddFeaturesFromSplitString(bool smp, const std::vector<std::string>& features,
+      AddFeaturesFromSplitString(const std::vector<std::string>& features,
                                  std::string* error_msg) const = 0;
 
  private:
-  const bool smp_;
-
   DISALLOW_COPY_AND_ASSIGN(InstructionSetFeatures);
 };
 std::ostream& operator<<(std::ostream& os, const InstructionSetFeatures& rhs);