iwlwifi: pcie: don't crash when rx queues aren't allocated in interrupt

WARNING is better than crashing. Since this happened to me,
be on the safe side.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210210142629.d4651427fcda.I1bcecb73676d039e2521309c07fc6b6314a90546@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/pcie/rx.c

@@ -1658,6 +1658,9 @@ irqreturn_t iwl_pcie_irq_rx_msix_handler(int irq, void *dev_id)
 	if (WARN_ON(entry->entry >= trans->num_rx_queues))
 		return IRQ_NONE;
 
+	if (WARN_ONCE(!rxq, "Got MSI-X interrupt before we have Rx queues"))
+		return IRQ_NONE;
+
 	lock_map_acquire(&trans->sync_cmd_lockdep_map);
 
 	local_bh_disable();