Make sim auxilary map part of regnum. Implement dump_tdep.

	* arc-tdep.c (struct arc_sim_aux_map_entry): Moved to arc-tdep.h
	(arc_sim_aux_map_size, arc_sim_aux_map): Deleted.
	(arc_tdesc_sim_aux_register): sim_aux_map is now part of regnum.
	(arc_gdbarch_init): Build temporary sim_aux_map and copy
	permanently into regnum structure. Initialize sim_aux_map and
	sim_aux_map_size entries in arg_regnum.
	(arc_dump_tdep): Implement contents.
	(sim_aux_reg_lookup): Get data from regnum associated with
	target_gdbarch.
	* arc-tdep.h (struct arc_sim_aux_map_entry): Created.
	(struct arc_regnum): Add sim_aux_map and sim_aux_map_size fields.