NetworkPkg:Enable Http Boot over Ipv6 stack

Add new features to support Http boot over ipv6 stack.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18743 6f19259b-4bc3-4df7-8a09-765794883524

NetworkPkg/HttpDxe/HttpDns.h

@@ -35,4 +35,24 @@ HttpDns4 (
      OUT EFI_IPv4_ADDRESS         *IpAddress                
   );
 
+/**
+  Retrieve the host address using the EFI_DNS6_PROTOCOL.
+
+  @param[in]  HttpInstance        Pointer to HTTP_PROTOCOL instance.
+  @param[in]  HostName            Pointer to buffer containing hostname.
+  @param[out] IpAddress           On output, pointer to buffer containing IPv6 address.
+
+  @retval EFI_SUCCESS             Operation succeeded.
+  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
+  @retval EFI_DEVICE_ERROR        An unexpected network error occurred.
+  @retval Others                  Other errors as indicated.
+  
+**/
+EFI_STATUS
+HttpDns6 (
+  IN     HTTP_PROTOCOL            *HttpInstance,
+  IN     CHAR16                   *HostName,
+     OUT EFI_IPv6_ADDRESS         *IpAddress                
+  );
+
 #endif