Docs/admin-guide/mm/damon/start: mention the dependency as sysfs instead of debugfs

'Getting Started' document of DAMON says DAMON user-space tool, damo[1],
is using DAMON debugfs interface, and therefore it needs to ensure debugfs
is mounted.  However, the latest version of the tool is using DAMON sysfs
interface.  Moreover, DAMON debugfs interface is going to be deprecated as
announced by commit b1840272 ("Docs/admin-guide/mm/damon/usage:
document DAMON sysfs interface").

This commit therefore update the document to tell readers about DAMON
sysfs interface dependency instead and never mention about debugfs
interface, which will be deprecated.

[1] https://github.com/awslabs/damo

Link: https://lkml.kernel.org/r/20220909202901.57977-7-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/admin-guide/mm/damon/start.rst

@@ -29,16 +29,9 @@ called DAMON Operator (DAMO).  It is available at
 https://github.com/awslabs/damo.  The examples below assume that ``damo`` is on
 your ``$PATH``.  It's not mandatory, though.
 
-Because DAMO is using the debugfs interface (refer to :doc:`usage` for the
-detail) of DAMON, you should ensure debugfs is mounted.  Mount it manually as
-below::
-
-    # mount -t debugfs none /sys/kernel/debug/
-
-or append the following line to your ``/etc/fstab`` file so that your system
-can automatically mount debugfs upon booting::
-
-    debugfs /sys/kernel/debug debugfs defaults 0 0
+Because DAMO is using the sysfs interface (refer to :doc:`usage` for the
+detail) of DAMON, you should ensure :doc:`sysfs </filesystems/sysfs>` is
+mounted.
 
 
 Recording Data Access Patterns