Check error return from bfd_canonicalize_dynamic_reloc

Check error return from bfd_canonicalize_dynamic_reloc

Since bfd_canonicalize_dynamic_reloc returns -1 on error, check it in
_bfd_x86_elf_get_synthetic_symtab.

	PR ld/22148
	* elfxx-x86.c (_bfd_x86_elf_get_synthetic_symtab): Check error
	return from bfd_canonicalize_dynamic_reloc.