libc: Add missing fdatasync() implementation

Change-Id: I04bb655d77e414021e1f2a973329167ad76ca1c4
diff --git a/libc/arch-arm/syscalls/fdatasync.S b/libc/arch-arm/syscalls/fdatasync.S
new file mode 100644
index 0000000..5981a80
--- /dev/null
+++ b/libc/arch-arm/syscalls/fdatasync.S
@@ -0,0 +1,19 @@
+/* autogenerated by gensyscalls.py */
+#include <sys/linux-syscalls.h>
+
+    .text
+    .type fdatasync, #function
+    .globl fdatasync
+    .align 4
+    .fnstart
+
+fdatasync:
+    .save   {r4, r7}
+    stmfd   sp!, {r4, r7}
+    ldr     r7, =__NR_fdatasync
+    swi     #0
+    ldmfd   sp!, {r4, r7}
+    movs    r0, r0
+    bxpl    lr
+    b       __set_syscall_errno
+    .fnend