ibm: hypervisor-network-mgr: adjust includes and fwd declarations

clang-18 with C++23 complains as follows:

```
/usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/unique_ptr.h:97:16: error: invalid application of 'sizeof' to an incomplete type 'phosphor::network::HypSysConfig'
   97 |         static_assert(sizeof(_Tp)>0,
...
../src/ibm/hypervisor-network-mgr-src/hyp_network_manager.hpp:159:32: note: in instantiation of member function 'std::unique_ptr<phosphor::network::HypSysConfig>::~unique_ptr' requested here
  159 |     SystemConfPtr systemConf = nullptr;
```

Get rid of the forward declaration and adjust some of the include
directives to satisfy clang.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Id2ebe1f5f7fce4962c0e3ffdf04bcaa476772e9a
diff --git a/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.cpp b/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.cpp
index 195b2c0..eae0c67 100644
--- a/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.cpp
+++ b/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.cpp
@@ -1,5 +1,7 @@
 #include "hyp_ethernet_interface.hpp"
 
+#include "hyp_network_manager.hpp"
+
 namespace phosphor
 {
 namespace network
diff --git a/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.hpp b/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.hpp
index 5fce963..c17095c 100644
--- a/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.hpp
+++ b/src/ibm/hypervisor-network-mgr-src/hyp_ethernet_interface.hpp
@@ -1,6 +1,5 @@
 #pragma once
 
-#include "hyp_network_manager.hpp"
 #include "xyz/openbmc_project/Network/IP/Create/server.hpp"
 
 #include <phosphor-logging/elog-errors.hpp>
diff --git a/src/ibm/hypervisor-network-mgr-src/hyp_network_manager.hpp b/src/ibm/hypervisor-network-mgr-src/hyp_network_manager.hpp
index f01a4b9..8a5f217 100644
--- a/src/ibm/hypervisor-network-mgr-src/hyp_network_manager.hpp
+++ b/src/ibm/hypervisor-network-mgr-src/hyp_network_manager.hpp
@@ -12,9 +12,6 @@
 namespace network
 {
 
-class HypEthInterface;
-class HypSysConfig;
-
 using biosAttrName = std::string;
 using biosAttrType = std::string;
 using biosAttrIsReadOnly = bool;
diff --git a/src/ibm/hypervisor-network-mgr-src/hyp_sys_config.hpp b/src/ibm/hypervisor-network-mgr-src/hyp_sys_config.hpp
index 5a6fd39..67bc45a 100644
--- a/src/ibm/hypervisor-network-mgr-src/hyp_sys_config.hpp
+++ b/src/ibm/hypervisor-network-mgr-src/hyp_sys_config.hpp
@@ -1,5 +1,4 @@
 #pragma once
-#include "hyp_network_manager.hpp"
 
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/server/object.hpp>
diff --git a/test/ibm/hypervisor-network-mgr-test/mock_hyp_sys_config.hpp b/test/ibm/hypervisor-network-mgr-test/mock_hyp_sys_config.hpp
index 8898b31..e765bb1 100644
--- a/test/ibm/hypervisor-network-mgr-test/mock_hyp_sys_config.hpp
+++ b/test/ibm/hypervisor-network-mgr-test/mock_hyp_sys_config.hpp
@@ -2,6 +2,7 @@
 
 #include "config.h"
 
+#include "hyp_network_manager.hpp"
 #include "hyp_sys_config.hpp"
 
 #include <gmock/gmock.h>