PR28165, buffer overflow in elf32-rx.c:rx_info_to_howto_rela

	PR 28165
	* elf32-rx.c (rx_elf_howto_table): Add missing empty entries.
	(rx_info_to_howto_rela): Assert rx_elf_howto_table is correct size.
	Use actual size when sanity checking r_type.