* mips.h: Document new field descriptors +Q.

    * mips.h: Document new field descriptors +Q.
        (OP_SH_SEQI, OP_MASK_SEQI): New bit mask and shift count for SEQI.

opcodes/

        * mips-dis.c (print_insn_args): Handle field descriptor +Q.
        * mips-opc.c (mips_builtin_opcodes): Add Octeon instructions seq,
        seqi, sne and snei.

gas/

        * config/tc-mips.c (validate_mips_insn): Handle field descriptor +Q.
        (mips_ip): Likewise.
        (macro_build): Likewise.
        (CPU_HAS_SEQ): New macro.
        (macro2) <M_SEQ_I, M_SNE_I>: Use it.  Emit seq/sne and seqi/snei.

gas/testsuite/

        * gas/mips/octeon.s, gas/mips/octeon.d: Add tests for seq* and sne*.
        * gas/mips/octeon-ill.s, gas/mips/octeon-ill.s: Add tests for seqi
        and snei.