[CodeGen] Remove unused function isMSInlineAsm (#69132)

The last use was removed by:

  commit ee08897
  Author: Reid Kleckner <[email protected]>
  Date:   Tue Dec 10 18:27:32 2013 +0000

Author: kazutakahirata

llvm/include/llvm/CodeGen/MachineInstr.h

@@ -1365,12 +1365,6 @@ class MachineInstr
            getOpcode() == TargetOpcode::INLINEASM_BR;
   }
 
-  /// FIXME: Seems like a layering violation that the AsmDialect, which is X86
-  /// specific, be attached to a generic MachineInstr.
-  bool isMSInlineAsm() const {
-    return isInlineAsm() && getInlineAsmDialect() == InlineAsm::AD_Intel;
-  }
-
   bool isStackAligningInlineAsm() const;
   InlineAsm::AsmDialect getInlineAsmDialect() const;