[SCSI] scsi_transport_sas: make minimum and maximum linkrate settable quantities

According to SPEC, the minimum_linkrate and maximum_linkrate should be
settable by the user.  This patch introduces a callback that allows the
sas class to pass these settings on to the driver.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/include/scsi/scsi_transport_sas.h b/include/scsi/scsi_transport_sas.h
index 87de518..5302437 100644
--- a/include/scsi/scsi_transport_sas.h
+++ b/include/scsi/scsi_transport_sas.h
@@ -150,12 +150,18 @@
 #define transport_class_to_sas_port(cdev) \
 	dev_to_sas_port((cdev)->dev)
 
+struct sas_phy_linkrates {
+	enum sas_linkrate maximum_linkrate;
+	enum sas_linkrate minimum_linkrate;
+};
+
 /* The functions by which the transport class and the driver communicate */
 struct sas_function_template {
 	int (*get_linkerrors)(struct sas_phy *);
 	int (*get_enclosure_identifier)(struct sas_rphy *, u64 *);
 	int (*get_bay_identifier)(struct sas_rphy *);
 	int (*phy_reset)(struct sas_phy *, int);
+	int (*set_phy_speed)(struct sas_phy *, struct sas_phy_linkrates *);
 };