iwlwifi: allow rate-limited error messages

Sometimes we might want to have an error message for something
related to TX/RX, but if that somehow happens frequently it'll
overwhelm the logs. Add IWL_ERR_LIMIT() to alleviate that by
rate-limiting those messages.

To do this, rework __iwl_err() a bit to have a mode argument
instead of passing yet another (bool) argument to it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211017162352.2cb1e6b75672.Iec5b1c1bcc6ebc87c586921a6c5c2a937f49e83c@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>