Kernel: Rename PCI::DeviceController => PCI::Device

Now that the old PCI::Device was removed, we can complete the PCI
changes by making the PCI::DeviceController to be named PCI::Device.

Really the entire purpose and the distinction between the two was about
interrupts, but since this is no longer a problem, just rename it to
simplify things further.

Kernel/Bus/PCI/Device.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+#include <Kernel/Bus/PCI/Definitions.h>
+
+namespace Kernel {
+class PCI::Device {
+public:
+    Address pci_address() const { return m_pci_address; };
+
+    virtual ~Device() = default;
+    void enable_pin_based_interrupts() const;
+    void disable_pin_based_interrupts() const;
+
+    bool is_msi_capable() const;
+    bool is_msix_capable() const;
+
+    void enable_message_signalled_interrupts();
+    void disable_message_signalled_interrupts();
+
+    void enable_extended_message_signalled_interrupts();
+    void disable_extended_message_signalled_interrupts();
+
+protected:
+    explicit Device(Address pci_address);
+
+private:
+    Address m_pci_address;
+};
+}