syscall_defines: Add uring to arm64
syscall_defines: Add uring to arm64

I missed adding uring to arm64, fix that.

TEST=emerge-arm64-generic crosvm compiles.

Change-Id: I0b8d5c41b51c52e89dd8d2fdaf0a8a19aca90446
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2247098
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Reviewed-by: Stephen Barber <7719587e4b5a49340661b214ec85602f3918d06f@chromium.org>
Tested-by: Dylan Reid <c791bfe44996c1eed9c7149a0c5f12a86d58eb85@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Commit-Queue: Dylan Reid <c791bfe44996c1eed9c7149a0c5f12a86d58eb85@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm