mei: show the HBM protocol versions in the device attributes

The HBM protocol version is negotiated during the setup phase, then settled
on a highest possible common version of the driver and the firmware.
The sysfs API advertises both negotiated and driver supported versions
in the device attributes.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-class-mei

@@ -29,3 +29,19 @@ Description:	Display fw status registers content
 		Also number of registers varies between 1 and 6
 		depending on generation.
 
+What:		/sys/class/mei/meiN/hbm_ver
+Date:		Aug 2016
+KernelVersion:	4.9
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:	Display the negotiated HBM protocol version.
+
+		The HBM protocol version negotiated
+		between the driver and the device.
+
+What:		/sys/class/mei/meiN/hbm_ver_drv
+Date:		Aug 2016
+KernelVersion:	4.9
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:	Display the driver HBM protocol version.
+
+		The HBM protocol version supported by the driver.