Documentation/ABI: Add new attribute for mlxreg-io sysfs interfaces

Add documentation for the new attributes for systems of type MQM87xx,
MSN34xx, MSN37xx. It includes the attributes related to ComEx resets,
system platform reset, JTAG interface enabling, additional CPLD device.
All the above system are equipped with ComEX board, have JTAG selector
and extra CPLD.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
[dvhart: Change kernel version from 5.0 to 4.21 until we know for sure]
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

Documentation/ABI/stable/sysfs-driver-mlxreg-io

@@ -12,7 +12,6 @@ Description:	This file shows ASIC health status. The possible values are:
 What:		/sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
 							cpld1_version
 							cpld2_version
-
 Date:		June 2018
 KernelVersion:	4.19
 Contact:	Vadim Pasternak <vadimpmellanox.com>
@@ -21,6 +20,28 @@ Description:	These files show with which CPLD versions have been burned
 
 		The files are read only.
 
+What:		/sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
+							cpld3_version
+
+Date:		November 2018
+KernelVersion:	4.21
+Contact:	Vadim Pasternak <vadimpmellanox.com>
+Description:	These files show with which CPLD versions have been burned
+		on LED board.
+
+		The files are read only.
+
+What:		/sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
+							jtag_enable
+
+Date:		November 2018
+KernelVersion:	4.21
+Contact:	Vadim Pasternak <vadimpmellanox.com>
+Description:	These files enable and disable the access to the JTAG domain.
+		By default access to the JTAG domain is disabled.
+
+		The file is read/write.
+
 What:		/sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/select_iio
 Date:		June 2018
 KernelVersion:	4.19
@@ -76,3 +97,21 @@ Description:	These files show the system reset cause, as following: power
 		reset cause.
 
 		The files are read only.
+
+What:		/sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
+						reset_comex_pwr_fail
+						reset_from_comex
+						reset_system
+						reset_voltmon_upgrade_fail
+
+Date:		November 2018
+KernelVersion:	4.21
+Contact:	Vadim Pasternak <vadimpmellanox.com>
+Description:	These files show the system reset cause, as following: ComEx
+		power fail, reset from ComEx, system platform reset, reset
+		due to voltage monitor devices upgrade failure,
+		Value 1 in file means this is reset cause, 0 - otherwise.
+		Only one bit could be 1 at the same time, representing only
+		the last reset cause.
+
+		The files are read only.