mm/damon/dbgfs: use kmalloc for allocating only one element

Use kmalloc(...) rather than kmalloc_array(1, ...) because the number of
elements we are specifying in this case is 1, kmalloc would accomplish the
same thing and we can simplify.

Link: https://lkml.kernel.org/r/20220808220019.1680469-1-klee33@uw.eduSigned-off-by: Kenneth Lee <klee33@uw.edu>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/dbgfs.c

@@ -1044,7 +1044,7 @@ static int __init __damon_dbgfs_init(void)
 				fops[i]);
 	dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]);
 
-	dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL);
+	dbgfs_dirs = kmalloc(sizeof(dbgfs_root), GFP_KERNEL);
 	if (!dbgfs_dirs) {
 		debugfs_remove(dbgfs_root);
 		return -ENOMEM;