Always count the NULL entry in dynamic symbol table

Always count the NULL entry in dynamic symbol table

There is an unused NULL entry at the head of dynamic symbol table which
we must account for in our count even if the table is empty or unused
since it is intended for the mandatory DT_SYMTAB tag (.dynsym section)
in .dynamic section.

	* elf-bfd.h (elf_link_hash_table): Update comments for
	dynsymcount.
	* elflink.c (_bfd_elf_link_renumber_dynsyms): Always count for
	the unused NULL entry at the head of dynamic symbol table.
	(bfd_elf_size_dynsym_hash_dynstr): Remove dynsymcount != 0
	checks.