m68k: Support for jump visualization in disassembly

opcodes/
	* m68k-dis.c (m68k_opcode_to_insn_type): Define.
	(match_insn_m68k): Call it to set insn_type.
	(print_insn_arg) [case 'B']: Set branch target address.
	(print_insn_m68k): Set insn_info_valid.