include/opcode/

	include/opcode/
	* mips.h (INSN_ISA*): Redefine certain values as an
	enumeration.  Update comments.
	(mips_isa_table): New.
	(ISA_MIPS*): Redefine to match enumeration.
	(OPCODE_IS_MEMBER): Modify to correctly test new INSN_ISA*
	values.

	opcodes/
	* mips-opc.c (I3_32, I3_33, I4_32, I4_33, I5_33): New.
	(mips_builtin_opcodes): Use these new I* values.