mac802154: Fix an always true condition

mac802154: Fix an always true condition

At this stage we simply do not care about the delayed work value,
because active scan is not yet supported, so we can blindly queue
another work once a beacon has been sent.

It fixes a smatch warning:
    mac802154_beacon_worker() warn: always true condition
    '(local->beacon_interval >= 0) => (0-u32max >= 0)'

Fixes: 3accf4762734 ("mac802154: Handle basic beaconing")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20230214135035.1202471-6-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>