ABI: sysfs-bus-mdio: add alternate What for mdio symbols

Not all sysfs nodes are shown under:
	/sys/bus/mdio_bus/devices/...
They can also be at:
	/sys/class/mdio_bus/.../

So, update the What: entries to allow both.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/aa51f6c2d482b28a349ba67e2a3904564e67496b.1632750608.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-mdio

 What:          /sys/bus/mdio_bus/devices/.../statistics/
+What:          /sys/class/mdio_bus/.../statistics/
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -7,6 +8,7 @@ Description:
 		MDIO bus address statistics.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/transfers
+What:          /sys/class/mdio_bus/.../transfers
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -14,6 +16,7 @@ Description:
 		Total number of transfers for this MDIO bus.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/errors
+What:          /sys/class/mdio_bus/.../statistics/errors
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -21,6 +24,7 @@ Description:
 		Total number of transfer errors for this MDIO bus.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/writes
+What:          /sys/class/mdio_bus/.../statistics/writes
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -28,6 +32,7 @@ Description:
 		Total number of write transactions for this MDIO bus.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/reads
+What:          /sys/class/mdio_bus/.../statistics/reads
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -35,6 +40,7 @@ Description:
 		Total number of read transactions for this MDIO bus.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/transfers_<addr>
+What:          /sys/class/mdio_bus/.../statistics/transfers_<addr>
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -42,6 +48,7 @@ Description:
 		Total number of transfers for this MDIO bus address.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/errors_<addr>
+What:          /sys/class/mdio_bus/.../statistics/errors_<addr>
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -49,6 +56,7 @@ Description:
 		Total number of transfer errors for this MDIO bus address.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/writes_<addr>
+What:          /sys/class/mdio_bus/.../statistics/writes_<addr>
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org
@@ -56,6 +64,7 @@ Description:
 		Total number of write transactions for this MDIO bus address.
 
 What:          /sys/bus/mdio_bus/devices/.../statistics/reads_<addr>
+What:          /sys/class/mdio_bus/.../statistics/reads_<addr>
 Date:          January 2020
 KernelVersion: 5.6
 Contact:       netdev@vger.kernel.org