Add some methods to dwarf2_per_cu_data

Add some methods to dwarf2_per_cu_data

This changes a few helper functions to be methods on
dwarf2_per_cu_data.

2020-02-08  Tom Tromey  <tom@tromey.com>

	* dwarf2/loc.c (dwarf2_find_location_expression)
	(dwarf_evaluate_loc_desc::get_tls_address)
	(dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value)
	(rw_pieced_value, dwarf2_evaluate_loc_desc_full)
	(dwarf2_locexpr_baton_eval, dwarf2_evaluate_property)
	(dwarf2_compile_property_to_c)
	(dwarf2_loc_desc_get_symbol_read_needs)
	(dwarf2_compile_expr_to_ax, locexpr_describe_location)
	(locexpr_tracepoint_var_ref, locexpr_generate_c_location)
	(loclist_describe_location, loclist_tracepoint_var_ref)
	(loclist_generate_c_location): Update.
	* compile/compile-loc2c.c (do_compile_dwarf_expr_to_c): Update.
	* dwarf2/loc.h (dwarf2_per_cu_objfile, dwarf2_per_cu_addr_size)
	(dwarf2_per_cu_ref_addr_size, dwarf2_per_cu_offset_size)
	(dwarf2_per_cu_text_offset, dwarf2_version): Don't declare.
	* dwarf2/read.c (dwarf2_per_cu_data::objfile)
	(dwarf2_per_cu_data::addr_size)
	(dwarf2_per_cu_data::ref_addr_size)
	(dwarf2_per_cu_data::text_offset)
	(dwarf2_per_cu_data::addr_type): Now methods.
	(per_cu_header_read_in): Make per_cu "const".
	(dwarf2_version): Remove.
	(dwarf2_per_cu_data::int_type): Now a method.
	(dwarf2_per_cu_data::_addr_sized_int_type): Likewise.
	(set_die_type, read_array_type, read_subrange_index_type)
	(read_tag_string_type, read_subrange_type): Update.
	* dwarf2/read.h (struct dwarf2_per_cu_data) <addr_size,
	offset_size, ref_addr_size, text_offset, addr_type, version,
	objfile, int_type, addr_sized_int_type>: Declare methods.

Change-Id: I07a42fa26e00795352389fa7a0cc1c12997d26f7