Documentation/device_model/Drivers: Consistently use full paths

For directories under '/sys/', a sentence in 'Drivers' section sometimes
use full path and sometimes only directory name.  For better
consistency, this commit modify the sentence to consistently use the
full paths.  This commit also fixes a typo of 'class' directory.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>

Author: sjp38

Documentation/teaching/labs/device_model.rst

@@ -561,9 +561,9 @@ device.
 
 In sysfs, driver information has no single subdirectory associated; They can be
 found in the directory structure in different places: the loaded module is in
-``/sys/module``, in ``devices`` you can find the driver associated with
-each device, in ``classes`` the drivers belonging to a class, in ``/sys/bus``
-the drivers associated to each bus.
+``/sys/module``, in ``/sys/devices`` you can find the driver associated with
+each device, in ``/sys/class`` the drivers belonging to a class, in
+``/sys/bus`` the drivers associated to each bus.
 
 A device driver is identified by the structure :c:type:`struct device_driver`: