binutils: Handle DWARF5 DW_FORM_ref_addr and DW_UT_partial.

binutils: Handle DWARF5 DW_FORM_ref_addr and DW_UT_partial.

dwz in DWARF5 mode might produce DW_UT_partial unit types, which are
the same as DW_UT_compile unit types (but start with a DW_TAG_partial_unit)
and it might produce DW_FORM_ref_addr to create a reference between
units. Accept both constructs.

binutils/ChangeLog:

	* dwarf.c (read_and_display_attr_value): Handle DW_FORM_ref_addr
	for dwarf_version 5 just as version 3 and 4 (only 2 is different).
	(process_debug_info): Allow DW_UT_partial.