wifi: cfg80211: fix wiphy delayed work queueing

When a wiphy work is queued with timer, and then again
without a delay, it's started immediately but *also*
started again after the timer expires. This can lead,
for example, to warnings in mac80211's offchannel code
as reported by Jouni. Running the same work twice isn't
expected, of course. Fix this by deleting the timer at
this point, when queuing immediately due to delay=0.

Cc: stable@vger.kernel.org
Reported-by: Jouni Malinen <j@w1.fi>
Fixes: a3ee4dc8 ("wifi: cfg80211: add a work abstraction with special semantics")
Link: https://msgid.link/20240125095108.2feb0eaaa446.I4617f3210ed0e7f252290d5970dac6a876aa595b@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>