devices, vm-device: Move BusDevice and Bus into vm-device

This removes the dependency of the pci crate on the devices crate which
now only contains the device implementations themselves.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

devices/src/legacy/cmos.rs

@@ -5,8 +5,7 @@
 use libc::{clock_gettime, gmtime_r, time_t, timespec, tm, CLOCK_REALTIME};
 use std::cmp::min;
 use std::mem;
-
-use crate::BusDevice;
+use vm_device::BusDevice;
 
 const INDEX_MASK: u8 = 0x7f;
 const INDEX_OFFSET: u64 = 0x0;

devices/src/legacy/fwdebug.rs

@@ -7,7 +7,7 @@
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
 //
 
-use BusDevice;
+use vm_device::BusDevice;
 
 /// Provides firmware debug output via I/O port controls
 #[derive(Default)]

devices/src/legacy/i8042.rs

@@ -4,7 +4,7 @@
 
 use vmm_sys_util::eventfd::EventFd;
 
-use BusDevice;
+use vm_device::BusDevice;
 
 /// A i8042 PS/2 controller that emulates just enough to shutdown the machine.
 pub struct I8042Device {

devices/src/legacy/rtc_pl031.rs

@@ -12,9 +12,8 @@ use std::fmt;
 use std::sync::Arc;
 use std::time::Instant;
 use std::{io, result};
-
-use crate::BusDevice;
 use vm_device::interrupt::InterruptSourceGroup;
+use vm_device::BusDevice;
 
 // As you can see in https://static.docs.arm.com/ddi0224/c/real_time_clock_pl031_r1p3_technical_reference_manual_DDI0224C.pdf
 // at section 3.2 Summary of RTC registers, the total size occupied by this device is 0x000 -> 0xFFC + 4 = 0x1000.

devices/src/legacy/serial.rs

@@ -5,12 +5,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE-BSD-3-Clause file.
 
-use crate::BusDevice;
 use anyhow::anyhow;
 use std::collections::VecDeque;
 use std::sync::Arc;
 use std::{io, result};
 use vm_device::interrupt::InterruptSourceGroup;
+use vm_device::BusDevice;
 use vm_migration::{
     Migratable, MigratableError, Pausable, Snapshot, SnapshotDataSection, Snapshottable,
     Transportable,