[bfd] Ensure unique printable names for bfd archs

Remove duplicate entry in bfd_ft32_arch and bfd_rx_arch.

Fix printable name for bfd_mach_n1: "nh1" -> "n1".

	PR 28336
	* cpu-ft32.c (arch_info_struct): Remove "ft32" entry.
	* cpu-rx.c (arch_info_struct): Remove "rx" entry.
	* cpu-nds32.c (bfd_nds32_arch): Fix printable name for bfd_mach_n1
	entry.