This is required, as CONFIG_DAMON_DEBUGFS is enabled, and --alltests UML
builds will fail due to the missing config option otherwise.

Fixes: f4cba4bf ("mm/damon: rename CONFIG_DAMON_DBGFS to DAMON_DBGFS_DEPRECATED")
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>