[netif] fix typos in comments (#4520)
[netif] fix typos in comments (#4520)

lanyuwen/openthread,lanyuwen/openthread,chshu/openthread,openthread/openthread,chshu/openthread,abtink/openthread,lanyuwen/openthread,abtink/openthread,bukepo/openthread,srickardti/openthread,openthread/openthread,chshu/openthread,librasungirl/openthread,chshu/openthread,librasungirl/openthread,librasungirl/openthread,lanyuwen/openthread,jwhui/openthread,srickardti/openthread,abtink/openthread,openthread/openthread,chshu/openthread,bukepo/openthread,jwhui/openthread,lanyuwen/openthread,srickardti/openthread,bukepo/openthread,chshu/openthread,bukepo/openthread,abtink/openthread,jwhui/openthread,openthread/openthread,lanyuwen/openthread,jwhui/openthread,srickardti/openthread,librasungirl/openthread