wifi: iwlwifi: call napi_synchronize() before freeing rx/tx queues

When rx/tx queues are being freed, on a different CPU there could be
still rx flow running. Call napi_synchronize() to prevent such a race.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Co-developed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://lore.kernel.org/r/20230416154301.5171ee44dcc1.Iff18718540da412e084e7d8266447d40730600ed@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>