Kernel: Fix how socket closing works

Sockets are now closed only when they are not referenced any more. This
allows child process to close socket and still keep it open for the
parent.

kernel/kernel/FS/Inode.cpp

@@ -56,12 +56,6 @@ namespace Kernel
 		return true;
 	}
 
-	void Inode::on_close()
-	{
-		LockGuard _(m_mutex);
-		on_close_impl();
-	}
-
 	BAN::ErrorOr<BAN::RefPtr<Inode>> Inode::find_inode(BAN::StringView name)
 	{
 		LockGuard _(m_mutex);