vm-virtio: Remove stale comment from watchdog device ID

Device ID 35 for virtio watchdog was officially allocated and
merged into the Linux kernel UAPI headers as VIRTIO_ID_WATCHDOG
in kernel 5.15. The virtio specification v1.2 also lists device
ID 35 for the watchdog device type. Leaving the comment is
therefore misleading.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>

vm-virtio/src/lib.rs

@@ -39,7 +39,7 @@ pub enum VirtioDeviceType {
     Mem = 24,
     Fs = 26,
     Pmem = 27,
-    Watchdog = 35, // Temporary until official number allocated
+    Watchdog = 35,
     Unknown = 0xFF,
 }