ahci: Soften up the dmesg on SB600 PMP softreset failure recovery

Too strong words led to spurious bug reports: Novell bugzilla #527748,
RedHat bugzilla #468800. This patch is used to soften up the dmesg on
SB600 PMP softreset failure recovery, so as to remove the scariness and
concern from community.
Reported-by: Npgnet Dev <pgnet.dev@gmail.com>
Signed-off-by: NShane Huang <shane.huang@amd.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

drivers/ata/ahci.c

@@ -1773,7 +1773,8 @@ static int ahci_sb600_softreset(struct ata_link *link, unsigned int *class,
 		irq_sts = readl(port_mmio + PORT_IRQ_STAT);
 		if (irq_sts & PORT_IRQ_BAD_PMP) {
 			ata_link_printk(link, KERN_WARNING,
-					"failed due to HW bug, retry pmp=0\n");
+					"applying SB600 PMP SRST workaround "
+					"and retrying\n");
 			rc = ahci_do_softreset(link, class, 0, deadline,
 					       ahci_check_ready);
 		}