A new research note obtained by MacRumors suggests that Apple may be planning to unbundle the Lighting to 3.5mm Headphone Jack adapter from this year’s iPhone models. In the research note, Barclays analyst Blayne Curtis and his associates state “We currently model no dongle this year,” and Barclays has lowered its quarterly and yearly revenue guidance for Cirrus Logic — the supplier of audio component in the adapter — by up…