PR binutils/6773

    PR binutils/6773
        * arm-dis.c (arm_opcodes): Replace <prefix>addsubx with
        <prefix>asx.  Replace <prefix>subaddx with <prefix>sax.
        (thumb32_opcodes): Likewise.

        * gas/arm/arch7em.d: Replace expected disassembly of
        <prefix>addsubx with <prefix>asx.  Also replace <prefix>subaddx
        with <prefix>sax.
        * gas/arm/archv6.d: Likewise.
        * gas/arm/thumb32.d: Likewise.