linux-user: Conditionalize TUNSETVNETLE

This fixes the build for older ppc64 kernel headers.

Fixes: 6addf06
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/ioctls.h

@@ -748,8 +748,10 @@
   IOCTL(TUNSETQUEUE,     IOC_W, MK_PTR(MK_STRUCT(STRUCT_short_ifreq)))
   IOCTL(TUNSETIFINDEX ,  IOC_W, MK_PTR(TYPE_INT))
   /* TUNGETFILTER is not supported: see TUNATTACHFILTER. */
+#ifdef TUNSETVNETLE
   IOCTL(TUNSETVNETLE,    IOC_W, MK_PTR(TYPE_INT))
   IOCTL(TUNGETVNETLE,    IOC_R, MK_PTR(TYPE_INT))
+#endif
 #ifdef TUNSETVNETBE
   IOCTL(TUNSETVNETBE,    IOC_W, MK_PTR(TYPE_INT))
   IOCTL(TUNGETVNETBE,    IOC_R, MK_PTR(TYPE_INT))