NetworkPkg: Fix IPv6 boot failure in diff net segment issue
NetworkPkg: Fix IPv6 boot failure in diff net segment issue

This patch is used to fix HTTP IPv6 boot failure in diff net segment
issue. IPv6 gateway address should be registered before DNS query,
otherwise, DNS query will fail.

Cc: Ye Ting <fe1f30c12225d8cd094a72a37b5acbb01ee15159@intel.com>
Cc: Zhang Lubo <1ed5a37ea7f59966ee72cee136ab89437ba8fc11@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiaxin Wu <91f509c31e98a6df13950454fe51aea543223eaa@intel.com>
Reviewed-by: Zhang Lubo <1ed5a37ea7f59966ee72cee136ab89437ba8fc11@intel.com>

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2