libata: Fix display of sata speed

6.0 Gbps link speed was not decoded properly:
speed was reported at 3.0 Gbps only.

Tested: On a machine where libata reports 6.0 Gbps in
        /var/log/messages:
    ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)

    Before:
    	cat /sys/class/ata_link/link1/sata_spd
    	3.0 Gbps
    After:
    	cat /sys/class/ata_link/link1/sata_spd
    	6.0 Gbps
Signed-off-by: Gwendal Grignou <gwendal@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org

drivers/ata/libata-transport.c

@@ -321,25 +321,25 @@ int ata_tport_add(struct device *parent,
 /*
  * ATA link attributes
  */
+static int noop(int x) { return x; }
 
-
-#define ata_link_show_linkspeed(field)					\
+#define ata_link_show_linkspeed(field, format)			        \
 static ssize_t								\
 show_ata_link_##field(struct device *dev,				\
 		      struct device_attribute *attr, char *buf)		\
 {									\
 	struct ata_link *link = transport_class_to_link(dev);		\
 									\
-	return sprintf(buf,"%s\n", sata_spd_string(fls(link->field)));	\
+	return sprintf(buf, "%s\n", sata_spd_string(format(link->field))); \
 }
 
-#define ata_link_linkspeed_attr(field)					\
-	ata_link_show_linkspeed(field)					\
+#define ata_link_linkspeed_attr(field, format)				\
+	ata_link_show_linkspeed(field, format)				\
 static DEVICE_ATTR(field, S_IRUGO, show_ata_link_##field, NULL)
 
-ata_link_linkspeed_attr(hw_sata_spd_limit);
-ata_link_linkspeed_attr(sata_spd_limit);
-ata_link_linkspeed_attr(sata_spd);
+ata_link_linkspeed_attr(hw_sata_spd_limit, fls);
+ata_link_linkspeed_attr(sata_spd_limit, fls);
+ata_link_linkspeed_attr(sata_spd, noop);
 
 
 static DECLARE_TRANSPORT_CLASS(ata_link_class,