Don't generate dynamic relocation against weak undefined symbol if it
is resolved to zero. FIXME: UNDEFWEAK_NO_DYNAMIC_RELOC may need to be
checked in more places.
PR ld/22269
* elfnn-aarch64.c (elfNN_aarch64_final_link_relocate): Don't
generate dynamic relocation if UNDEFWEAK_NO_DYNAMIC_RELOC is
true.
(elfNN_aarch64_allocate_dynrelocs): Discard dynamic relocations
if UNDEFWEAK_NO_DYNAMIC_RELOC is true.