cc2538_rf: Don't use netdev_ieee802154_t for link layer address

[bergzand]

Contribution description

This PR modifies the behaviour of the cc2538_rf driver to not propagate the link layer address to the netdev_ieee802154_t struct. This helps the goal of separating the netdev and the ieee802154_t layer by another bit. The end goal is to remove the short and long address from the netdev_ieee802154_t struct and match the behaviour of the ethernet drivers.

The performance impact of this change should be negligible, the NETOPT_ADDRESS(_LONG) call is only used on initialization and by the ifconfig command.

Testing procedure

Test whether:

• ifconfig still shows the correct link layer addresses. These should not have changed between this PR and master.
• ping still works. This to verify that the link layer address is also properly configured in the radio, if the ping echo/reply fails, the address filter of the radio might be configured in the wrong endianness.

Issues/PRs references

related to #10401, part of #7736

disclaimer: I don't own a board with the cc2538 on it so I'm flying blind here. As long as the actual address getters work, the code should work.

[aabadie]

I don't own a board with the cc2538 on it so I'm flying blind here.

@bergzand, just in case, there are Zolertia Firefly (cc2538 based boards) deployed on the Lille site of IoT-LAB.

[bergzand]

@bergzand, just in case, there are Zolertia Firefly (cc2538 based boards) deployed on the Lille site of IoT-LAB.

I wasn't aware of that, thanks for letting me know.

[bergzand]

Tested with two firefly boards on the IoT-LAB, appears to work for me.

[smlng]

Tested with remote-revb, ACK!