mips: Check UNDEFWEAK_NO_DYNAMIC_RELOC

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
	* elfxx-mips.c (mips_elf_calculate_relocation): Don't generate
	dynamic relocation if UNDEFWEAK_NO_DYNAMIC_RELOC is true.
	(allocate_dynrelocs): Don't allocate dynamic relocations if
	UNDEFWEAK_NO_DYNAMIC_RELOC is true.