[virtio] Move virtio module from pvmfw to vmbase

for reuse in both pvmfw and rialo.

No code change in this cl.

Bug: 284462758
Test: m pvmfw_img
Change-Id: I225b495a2f8c1a49cb63ea69d60f01949bab3f05
diff --git a/pvmfw/src/main.rs b/pvmfw/src/main.rs
index c6baf6d..c826cd8 100644
--- a/pvmfw/src/main.rs
+++ b/pvmfw/src/main.rs
@@ -34,7 +34,6 @@
 mod instance;
 mod memory;
 mod rand;
-mod virtio;
 
 use crate::bcc::Bcc;
 use crate::dice::PartialInputs;
@@ -42,7 +41,6 @@
 use crate::fdt::modify_for_next_stage;
 use crate::helpers::GUEST_PAGE_SIZE;
 use crate::instance::get_or_generate_instance_salt;
-use crate::virtio::pci;
 use alloc::boxed::Box;
 use core::ops::Range;
 use diced_open_dice::{bcc_handover_parse, DiceArtifacts};
@@ -55,6 +53,7 @@
 use pvmfw_embedded_key::PUBLIC_KEY;
 use vmbase::memory::flush;
 use vmbase::memory::MEMORY;
+use vmbase::virtio::pci;
 
 const NEXT_BCC_SIZE: usize = GUEST_PAGE_SIZE;