PR16794, gold ignores R_386_GOTOFF addend

An R_386_GOTOFF relocation has an addend, typically used when a
symbol can be replaced by its section symbol plus an offset.
psymval->value(object,0) is quite wrong then, fix it.

	PR 16794
	* i386.cc (Target_i386::Relocate::relocate <R_386_GOTOFF>): Don't
	ignore addend, apply using pcrel32.
	* x86_64.cc (Target_x86_64::Relocate::relocate <R_X86_64_GOTOFF64>):
	Similarly use pcrel64.