MdeModulePkg: Fix default router table and interface missing error

Ip4StartAutoConfig() will always free its default router table and interface,
which may cause IP instance missing its correct default interface. e.g. when
the policy is dhcp, and one child is configured to use default address.

Cc: Ye Ting <ting.ye@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviwed-by: Ye Ting <ting.ye@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18245 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Impl.h

@@ -205,6 +205,8 @@ struct _IP4_SERVICE {
 
   EFI_EVENT                       ReconfigEvent;
 
+  BOOLEAN                         Reconfig;
+
   //
   // Underlying media present status. 
   //