This patch changes the behaviors of frame802154_has_panid() for frames
of frame version 0b10 so that it complies with the PAN ID Field Handling
specification in IEEE 802.15.4-2015. For the other frame versions, 0b00
and 0b01, no change is made in frame802154_has_panid().
For more information, please refer to:
https://github.com/contiki-os/contiki/pull/1914/
