mac802154: Clarify an expression

While going through the whole interface opening logic in my head I was
consistently bothered by the condition checking whether there was only
one interface of type NODE/COORD opened at the same time. What actually
bothered me was the fact that in one case we would use the wpan_dev
pointer directly while in the other case we would use the sdata pointer,
making it harder to differentiate both. In practice the condition should
be straightforward to read. IMHO dropping the wpan_dev indirection
allows to clarify the check.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20221026093502.602734-3-miquel.raynal@bootlin.com


Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>