kernel: Remove unnecessary includes

Removes unnecessary direct dependencies in some headers and also gets
rid of indirect dependencies that were being relied on to be included.

src/core/hle/kernel/server_session.cpp

@@ -5,6 +5,8 @@
 #include <tuple>
 #include <utility>
 
+#include "common/assert.h"
+#include "common/logging/log.h"
 #include "core/core.h"
 #include "core/hle/ipc_helpers.h"
 #include "core/hle/kernel/client_port.h"