Add missing import for kvm_pit_config in documentation examples

Author: karuboniru

kvm-ioctls/src/ioctls/vm.rs

@@ -422,6 +422,7 @@ impl VmFd {
     /// extern crate kvm_bindings;
     /// use kvm_ioctls::Kvm;
     /// use kvm_bindings::{kvm_reinject_control};
+    /// use kvm_bindings::kvm_pit_config;
     /// let kvm = Kvm::new().unwrap();
     /// let vm = kvm.create_vm().unwrap();
     /// vm.create_irq_chip().unwrap();
@@ -455,6 +456,7 @@ impl VmFd {
     /// ```rust
     /// extern crate kvm_ioctls;
     /// extern crate kvm_bindings;
+    /// use kvm_bindings::kvm_pit_config;
     /// use kvm_ioctls::Kvm;
     /// let kvm = Kvm::new().unwrap();
     /// let vm = kvm.create_vm().unwrap();