CHROMIUM: virtwl: use compat_ptr in compat_ioctl implementations

BUG=None
TEST=virtio_wl.c compiles

Change-Id: I5e00d8d98d48996bc1c7a61babe4ea291ed61cc7
Signed-off-by: Zach Reizner <zachr@google.com>
Reviewed-on: https://chromium-review.googlesource.com/865494
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
(cherry picked from commit efa89ecc24b75cc89384f715135ec25e1caa226d)
Reviewed-on: https://chromium-review.googlesource.com/957809