Hide accidentally-exposed __clock_nanosleep.

Bug: http://b/21858067
Change-Id: Iaa83a5e17cfff796aed4f641d0d14427614d9399
diff --git a/libc/arch-mips64/syscalls/___clock_nanosleep.S b/libc/arch-mips64/syscalls/___clock_nanosleep.S
new file mode 100644
index 0000000..e9fb316
--- /dev/null
+++ b/libc/arch-mips64/syscalls/___clock_nanosleep.S
@@ -0,0 +1,26 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(___clock_nanosleep)
+    .set push
+    .set noreorder
+    li v0, __NR_clock_nanosleep
+    syscall
+    bnez a3, 1f
+    move a0, v0
+    j ra
+    nop
+1:
+    move t0, ra
+    bal     2f
+    nop
+2:
+    .cpsetup ra, t1, 2b
+    LA t9,__set_errno_internal
+    .cpreturn
+    j t9
+    move ra, t0
+    .set pop
+END(___clock_nanosleep)
+.hidden ___clock_nanosleep