* ppc-opc.c (ISA_V2): Define and use for relevant BO field tests.

	* ppc-opc.c (ISA_V2): Define and use for relevant BO field tests.
	(valid_bo_pre_v2, valid_bo_post_v2): New functions, extracted from..
	(valid_bo): ..here.  When disassembling, accept either 'y' or 'at'
	type encoding on second pass.
	(powerpc_opcodes): Use ISA_V2 to enable branch insns rather than
	POWER4.
	* ppc-dis.c (print_insn_powerpc): Delete dialect_orig.  Instead
	ignore deprecated on second pass.