Fix several RFC compliance issues in DHCP6 driver as below.

Fix several RFC compliance issues in DHCP6 driver as below.
1. Client must ignore any Advertise message that includes a Status Code option containing the value NoAddrsAvail.
2. The elapsed-time should start from the current DHCP transaction.
3. Client should not change any information about addresses the client has recorded in the IA but not included in the IA from the server.
4. Client need to update to handle the error status code UnspecFail/UseMulticast/NotOnLink/NoBinding in the Reply message from server.
5. When the client receives a Reply message in response to a Renew/ Rebind message, the client examines each IA independently. For each IA in the original Renew/ Rebind message, the client sends a Renew/ Rebind if the IA is not in the Reply message.
6. Client should uses network byte order in IANA T1/T2 option
7. Client should discard any addresses for which the preferred lifetime is greater than the valid lifetime.

Signed-off-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Ouyang Qian <qian.ouyang@intel.com>
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14039 6f19259b-4bc3-4df7-8a09-765794883524