[posix] only update timeout with a lower value (#5119)
[posix] only update timeout with a lower value (#5119)


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