libata-sff: Reenable Port Multiplier after libata-sff remodeling.

Keep track of the link on the which the current request is in progress.
It allows support of links behind port multiplier.

Not all libata-sff is PMP compliant. Code for native BMDMA controller
does not take in accound PMP.

Tested on Marvell 7042 and Sil7526.

Signed-off-by: Gwendal Grignou <gwendal@google.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 7de282d..45fb296 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -724,6 +724,7 @@
 	struct ata_ioports	ioaddr;	/* ATA cmd/ctl/dma register blocks */
 	u8			ctl;	/* cache of ATA control register */
 	u8			last_ctl;	/* Cache last written value */
+	struct ata_link*	sff_pio_task_link; /* link currently used */
 	struct delayed_work	sff_pio_task;
 #ifdef CONFIG_ATA_BMDMA
 	struct ata_bmdma_prd	*bmdma_prd;	/* BMDMA SG list */
@@ -1595,7 +1596,7 @@
 extern void ata_sff_irq_clear(struct ata_port *ap);
 extern int ata_sff_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
 			    u8 status, int in_wq);
-extern void ata_sff_queue_pio_task(struct ata_port *ap, unsigned long delay);
+extern void ata_sff_queue_pio_task(struct ata_link *link, unsigned long delay);
 extern unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc);
 extern bool ata_sff_qc_fill_rtf(struct ata_queued_cmd *qc);
 extern unsigned int ata_sff_port_intr(struct ata_port *ap,