Add fileno_unlocked to support thread sanitizer.

Bug: 25392375
Change-Id: If3f92a0e08a53f4b59e01397e8efa307d8572349
diff --git a/libc/libc.mips.map b/libc/libc.mips.map
index 0c69c19..23123dc 100644
--- a/libc/libc.mips.map
+++ b/libc/libc.mips.map
@@ -1273,6 +1273,7 @@
     __pwrite_chk;
     __pwrite64_chk;
     __write_chk;
+    fileno_unlocked;
     getgrgid_r;
     getgrnam_r;
     preadv;