MIPS: N64: Wire getdents64(2)

As a relatively new ABI, N64 only had getdents syscall while other modern
architectures have getdents64.

This was noticed when Python 3.3 shifted to the latter one for aarch64.

[ralf@linux-mips.org: The history of getdents64 is a little complicated.
Commit 1a1d77dd589de5a567fa95e36aa6999c704ceca4 [Merge with 2.4.0-test7.]
added N64 getdents(2) to arch/mips64/kernel/scall_64.S as syscall 5213,
then dropped again in 578720675c44e54e8aa7c68f6dce59ed37ce3d3b [Overhaul
of the 64-bit syscall interface.  Now heritage free.] for 2.5.18 in 2002.]

Signed-off-by: Aron Xu <aron@debian.org>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5285/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index 36cfd40..97a5909 100644
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -423,4 +423,5 @@
 	PTR	sys_process_vm_writev		/* 5305 */
 	PTR	sys_kcmp
 	PTR	sys_finit_module
+	PTR	sys_getdents64
 	.size	sys_call_table,.-sys_call_table