mm/damon/dbgfs-test: fix is_target_id() change

DAMON kunit tests for DAMON debugfs interface fails because it still
assumes setting empty monitoring operations makes DAMON debugfs interface
believe the target of the context don't have pid.  This commit fixes the
kunit test fails by explicitly setting the context's monitoring operations
with the operations for the physical address space, which let debugfs
knows the target will not have pid.

Link: https://lkml.kernel.org/r/20220215184603.1479-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/damon/dbgfs-test.h

@@ -74,7 +74,7 @@ static void damon_dbgfs_test_set_targets(struct kunit *test)
 	char buf[64];
 
 	/* Make DAMON consider target has no pid */
-	ctx->ops = (struct damon_operations){};
+	damon_select_ops(ctx, DAMON_OPS_PADDR);
 
 	dbgfs_set_targets(ctx, 0, NULL);
 	sprint_target_ids(ctx, buf, 64);
@@ -111,6 +111,8 @@ static void damon_dbgfs_test_set_init_regions(struct kunit *test)
 	int i, rc;
 	char buf[256];
 
+	damon_select_ops(ctx, DAMON_OPS_PADDR);
+
 	dbgfs_set_targets(ctx, 3, NULL);
 
 	/* Put valid inputs and check the results */