[mle] process Active and Pending Timestamps in MLE Child Update Request (#2131)
[mle] process Active and Pending Timestamps in MLE Child Update Request (#2131)

This commit adds proper handling of Active and Pending Timestamp TLVs
that are included in parent-initiated MLE Child Update Requests.
fbsder/openthread,openthread/openthread,turon/openthread,fbsder/openthread,lanyuwen/openthread,xiaom-GitHub/openthread,erja-gp/openthread,mszczodrak/openthread,aeliot/openthread,fbsder/openthread,jwhui/openthread,bukepo/openthread,erja-gp/openthread,LeZhang2016/openthread,lanyuwen/openthread,srickardti/openthread,mszczodrak/openthread,bukepo/openthread,pvanhorn/openthread,pvanhorn/openthread,srickardti/openthread,gandreello/openthread,vaas-krish/openthread,librasungirl/openthread,librasungirl/openthread,LeZhang2016/openthread,LeZhang2016/openthread,aeliot/openthread,gandreello/openthread,gandreello/openthread,fbsder/openthread,georgecpr/openthread,gandreello/openthread,turon/openthread,mszczodrak/openthread,georgecpr/openthread,turon/openthread,jwhui/openthread,georgecpr/openthread,xiaom-GitHub/openthread,mszczodrak/openthread,xiaom-GitHub/openthread,bukepo/openthread,aeliot/openthread,xiaom-GitHub/openthread,xiaom-GitHub/openthread,vaas-krish/openthread,pvanhorn/openthread,jwhui/openthread,abtink/openthread,srickardti/openthread,vaas-krish/openthread,aeliot/openthread,lanyuwen/openthread,aeliot/openthread,LeZhang2016/openthread,srickardti/openthread,aeliot/openthread,chshu/openthread,erja-gp/openthread,mszczodrak/openthread,chshu/openthread,chshu/openthread,vaas-krish/openthread,gandreello/openthread,chshu/openthread,LeZhang2016/openthread,erja-gp/openthread,fbsder/openthread,vaas-krish/openthread,pvanhorn/openthread,abtink/openthread,librasungirl/openthread,xiaom-GitHub/openthread,turon/openthread,LeZhang2016/openthread,openthread/openthread,openthread/openthread,georgecpr/openthread,openthread/openthread,erja-gp/openthread,erja-gp/openthread,fbsder/openthread,abtink/openthread,georgecpr/openthread,gandreello/openthread,pvanhorn/openthread,mszczodrak/openthread,vaas-krish/openthread,librasungirl/openthread,jwhui/openthread,chshu/openthread,bukepo/openthread,lanyuwen/openthread,chshu/openthread,pvanhorn/openthread,abtink/openthread,lanyuwen/openthread,georgecpr/openthread,lanyuwen/openthread