wireless: Fix compile error with wifi & leds

Fix build error caused by commit
e82404ad ("iwlwifi: Select
LEDS_CLASS.") from David Miller:

Since MAC80211_LEDS is selected by wireless drivers it must select its
own dependencies otherwise a build error may occur (kbuild will select
the symbol regardless of "depends" constraints).

Signed-off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>