ANDROID: GKI: add netdev_stat_queue_sum to the virtual symbol list

In commit de02eb72 ("virtio-net: fix total qstat values"),
netdev_stat_queue_sum is now called in the virtio-net driver, so add it
to the symbol list for that module in order to fix the build.

Fixes: de02eb72 ("virtio-net: fix total qstat values")
Change-Id: Icfc8511edbb77e08df2c9c20819f3d218adf1fc5
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>