ahci: add HFLAG_YES_FBS and apply it to 88SE9128

88SE9128 can do FBS and sets it in HOST_CAP but forgets to set FBSCP
in PORT_CMD.  Implement AHCI_HFLAG_YES_FBS and apply it to 88SE9128.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/ahci.h

@@ -209,6 +209,7 @@ enum {
 							link offline */
 	AHCI_HFLAG_NO_SNTF		= (1 << 12), /* no sntf */
 	AHCI_HFLAG_NO_FPDMA_AA		= (1 << 13), /* no FPDMA AA */
+	AHCI_HFLAG_YES_FBS		= (1 << 14), /* force FBS cap on */
 
 	/* ap->flags bits */