Remove unnecessary `explicit` qualifiers on constructors.

Change-Id: Id12e392ad50f66a6e2251a68662b7959315dc567
diff --git a/compiler/utils/mips/assembler_mips.h b/compiler/utils/mips/assembler_mips.h
index 0d1b82c..df95dad 100644
--- a/compiler/utils/mips/assembler_mips.h
+++ b/compiler/utils/mips/assembler_mips.h
@@ -283,7 +283,7 @@
 // Slowpath entered when Thread::Current()->_exception is non-null
 class MipsExceptionSlowPath FINAL : public SlowPath {
  public:
-  explicit MipsExceptionSlowPath(MipsManagedRegister scratch, size_t stack_adjust)
+  MipsExceptionSlowPath(MipsManagedRegister scratch, size_t stack_adjust)
       : scratch_(scratch), stack_adjust_(stack_adjust) {}
   virtual void Emit(Assembler *sp_asm) OVERRIDE;
  private: