Revert "igb: Disable threaded IRQ for igb_msix_other"

This reverts commit 338c4d3.

Sebastian noticed the ISR indirectly acquires spin_locks, which are
sleeping locks under PREEMPT_RT, which leads to kernel splats.

Fixes: 338c4d3 ("igb: Disable threaded IRQ for igb_msix_other")
Reported-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Wander Lairson Costa <[email protected]>
Reviewed-by: Sebastian Andrzej Siewior <[email protected]>
Acked-by: Przemek Kitszel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: walac

drivers/net/ethernet/intel/igb/igb_main.c

@@ -907,7 +907,7 @@ static int igb_request_msix(struct igb_adapter *adapter)
 	int i, err = 0, vector = 0, free_vector = 0;
 
 	err = request_irq(adapter->msix_entries[vector].vector,
-			  igb_msix_other, IRQF_NO_THREAD, netdev->name, adapter);
+			  igb_msix_other, 0, netdev->name, adapter);
 	if (err)
 		goto err_out;