Kernel: Implement a PCI Serial Device driver

This simple driver simply finds a device in a device definitions list
and then sets up a SerialDevice instance based on the definition.

The driver currently only supports "WCH CH382 2S" pci serial boards,
as that is the only device available for me to test with, but most
other pci serial devices should be as easily addable as adding a
board_definitions entry.

Kernel/kprintf.cpp

@@ -7,6 +7,7 @@
 #include <AK/PrintfImplementation.h>
 #include <AK/Types.h>
 #include <Kernel/ConsoleDevice.h>
+#include <Kernel/Devices/PCISerialDevice.h>
 #include <Kernel/Graphics/Console/Console.h>
 #include <Kernel/Graphics/GraphicsManagement.h>
 #include <Kernel/IO.h>
@@ -34,6 +35,9 @@ int get_serial_debug()
 
 static void serial_putch(char ch)
 {
+    if (PCISerialDevice::is_available())
+        return PCISerialDevice::the().put_char(ch);
+
     static bool serial_ready = false;
     static bool was_cr = false;