ahci: kill 'intr_status'

This field in achi_port_priv was only used to support threaded
interrupts.  Now that we are hardirq only it can be deleted.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

drivers/ata/ahci.h

@@ -309,7 +309,6 @@ struct ahci_port_priv {
 	unsigned int		ncq_saw_d2h:1;
 	unsigned int		ncq_saw_dmas:1;
 	unsigned int		ncq_saw_sdb:1;
-	atomic_t		intr_status;	/* interrupts to handle */
 	spinlock_t		lock;		/* protects parent ata_port */
 	u32 			intr_mask;	/* interrupts to enable */
 	bool			fbs_supported;	/* set iff FBS is supported */