gdb/nds32: update features/nds32.c

After this commit:

  commit 7b7c365c5c663ffdfb2b3f696db35c23cdccd921
  Date:   Wed Sep 15 10:10:46 2021 +0200

      [bfd] Ensure unique printable names for bfd archs

The printable name field of the default nds32 bfd_arch_info changed
from 'n1h' to 'n1'.  As a consequence the generated feature file
within GDB should have been recreated.  Recreate it now.