Kernel: Move Lockable into its own header

Kernel/Net/IPv4Socket.h

@@ -10,7 +10,7 @@
 #include <AK/SinglyLinkedListWithCount.h>
 #include <Kernel/DoubleBuffer.h>
 #include <Kernel/KBuffer.h>
-#include <Kernel/Locking/Mutex.h>
+#include <Kernel/Locking/Lockable.h>
 #include <Kernel/Net/IPv4.h>
 #include <Kernel/Net/IPv4SocketTuple.h>
 #include <Kernel/Net/Socket.h>

Kernel/Net/LocalSocket.cpp

@@ -9,6 +9,8 @@
 #include <Kernel/Debug.h>
 #include <Kernel/FileSystem/FileDescription.h>
 #include <Kernel/FileSystem/VirtualFileSystem.h>
+#include <Kernel/Locking/Lockable.h>
+#include <Kernel/Locking/Mutex.h>
 #include <Kernel/Net/LocalSocket.h>
 #include <Kernel/Process.h>
 #include <Kernel/StdLib.h>

Kernel/Net/Routing.h

@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <Kernel/Locking/Lockable.h>
 #include <Kernel/Net/NetworkAdapter.h>
 #include <Kernel/Thread.h>
 

Kernel/Net/TCPSocket.cpp

@@ -9,6 +9,7 @@
 #include <Kernel/Debug.h>
 #include <Kernel/Devices/RandomDevice.h>
 #include <Kernel/FileSystem/FileDescription.h>
+#include <Kernel/Locking/Lockable.h>
 #include <Kernel/Net/EthernetFrameHeader.h>
 #include <Kernel/Net/IPv4.h>
 #include <Kernel/Net/NetworkAdapter.h>

Kernel/Net/UDPSocket.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/Singleton.h>
 #include <Kernel/Devices/RandomDevice.h>
+#include <Kernel/Locking/Mutex.h>
 #include <Kernel/Net/NetworkAdapter.h>
 #include <Kernel/Net/Routing.h>
 #include <Kernel/Net/UDP.h>

Kernel/Net/UDPSocket.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <Kernel/KResult.h>
+#include <Kernel/Locking/Lockable.h>
 #include <Kernel/Net/IPv4Socket.h>
 
 namespace Kernel {