* mips-opc.c: Change div machine instruction to be z,s,t rather

	* mips-opc.c: Change div machine instruction to be z,s,t rather
	than s,t.  Change div macro to be d,v,t rather than d,s,t.
	Likewise for divu, ddiv, ddivu.  Added z,s,t case for drem, dremu,
	rem and remu which generates only the corresponding div
	instruction.  This is for compatibility with the MIPS assembler,
	which only generates the simple machine instruction when an
	explicit destination of $0 is used.
	* mips-dis.c (print_insn_arg): Handle 'z' (always register zero).