misc: Upgrade to use the vm-memory crate w/ dirty-page-tracking

As the first step to complete live-migration with tracking dirty-pages
written by the VMM, this commit patches the dependent vm-memory crate to
the upstream version with the dirty-page-tracking capability. Most
changes are due to the updated `GuestMemoryMmap`, `GuestRegionMmap`, and
`MmapRegion` structs which are taking an additional generic type
parameter to specify what 'bitmap backend' is used.

The above changes should be transparent to the rest of the code base,
e.g. all unit/integration tests should pass without additional changes.

Signed-off-by: Bo Chen <chen.bo@intel.com>

vmm/src/cpu.rs

@@ -19,6 +19,7 @@ use crate::memory_manager::MemoryManager;
 use crate::seccomp_filters::{get_seccomp_filter, Thread};
 #[cfg(target_arch = "x86_64")]
 use crate::vm::physical_bits;
+use crate::GuestMemoryMmap;
 use crate::CPU_MANAGER_SNAPSHOT_ID;
 #[cfg(feature = "acpi")]
 use acpi_tables::{aml, aml::Aml, sdt::Sdt};
@@ -43,7 +44,7 @@ use std::{cmp, io, result, thread};
 use vm_device::BusDevice;
 #[cfg(feature = "acpi")]
 use vm_memory::GuestAddress;
-use vm_memory::{GuestMemoryAtomic, GuestMemoryMmap};
+use vm_memory::GuestMemoryAtomic;
 use vm_migration::{
     Migratable, MigratableError, Pausable, Snapshot, SnapshotDataSection, Snapshottable,
     Transportable,
@@ -1775,6 +1776,7 @@ mod tests {
 #[cfg(target_arch = "aarch64")]
 #[cfg(test)]
 mod tests {
+    use crate::GuestMemoryMmap;
     use arch::aarch64::layout;
     use arch::aarch64::regs::*;
     use hypervisor::kvm::aarch64::{is_system_register, MPIDR_EL1};
@@ -1784,7 +1786,7 @@ mod tests {
     };
     use hypervisor::{arm64_core_reg_id, offset__of};
     use std::mem;
-    use vm_memory::{GuestAddress, GuestMemoryMmap};
+    use vm_memory::GuestAddress;
 
     #[test]
     fn test_setup_regs() {