[GOLD] Output_data_got tidy

[GOLD] Output_data_got tidy

Some Output_data_got methods already have support for addends, but
were implemented as separate methods.  This removes unnecessary code
duplication.

Relobj::local_has_got_offset and others there get a similar treatment.
Comments are removed since it should be obvious without a comment, and
the existing comments are not precisely what the code does.  For
example, a local_has_got_offset call without an addend does not return
whether the local symbol has *a* GOT offset of type GOT_TYPE, it
returns whether there is a GOT entry of type GOT_TYPE for the symbol
with addend of zero.

	PR 28192
	* output.h (Output_data_got::add_local): Make addend optional.
	(Output_data_got::add_local_with_rel): Likewise.
	(Output_data_got::add_local_pair_with_rel): Likewise.
	* output.cc (Output_data_got::add_local): Delete overload
	without addend.
	(Output_data_got::add_local_with_rel): Likewise.
	(Output_data_got::add_local_pair_with_rel): Likewise.
	* object.h (Relobj::local_has_got_offset): Make addend optional.
	Delete overload without addend later.  Update comment.
	(Relobj::local_got_offset): Likewise.
	(Relobj::set_local_got_offset): Likewise.