On older devices (before unified image!) we can end up calling
stop_device from an rfkill interrupt. However, in stop_device
we attempt to synchronize IRQs, which then of course deadlocks.

Avoid this by checking the context, if running from the IRQ
thread then don't synchronize. This wouldn't be correct on a
new device since RSS is supported, but older devices only have
a single interrupt/queue.

Fixes: 37fb29bd ("wifi: iwlwifi: pcie: synchronize IRQs before NAPI")
Reviewed-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20231215111335.59aab00baed7.Iadfe154d6248e7f9dfd69522e5429dbbd72925d7@changeid