Create sdynrelro for elfn32 mips too

* elfn32-mips.c (elf_backend_want_dynrelro): Define.

bfd/ChangeLog

@@ -1,3 +1,7 @@
+2016-12-31  Alan Modra  <amodra@gmail.com>
+
+	* elfn32-mips.c (elf_backend_want_dynrelro): Define.
+
 2016-12-31  Dimitar Dimitrov  <dimitar@dinux.eu>
 
 	* archures.c: Add bfd_arch_pru.

bfd/elfn32-mips.c

@@ -3687,6 +3687,7 @@ static const struct ecoff_debug_swap mips_elf32_ecoff_debug_swap = {
 #define elf_backend_ecoff_debug_swap	&mips_elf32_ecoff_debug_swap
 
 #define elf_backend_got_header_size	(4 * MIPS_RESERVED_GOTNO)
+#define elf_backend_want_dynrelro	1
 
 /* MIPS n32 ELF can use a mixture of REL and RELA, but some Relocations
    work better/work only in RELA, so we default to this.  */