selftests: cgroup: remove redundant enabling of memory controller

Memory controller is already enabled in main which invokes the test, hence
this does not need to be done in test_no_kmem_bypass.

Link: https://lkml.kernel.org/r/20240502200529.4193651-2-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: uarif1

tools/testing/selftests/cgroup/test_zswap.c

@@ -364,8 +364,6 @@ static int test_no_kmem_bypass(const char *root)
 	trigger_allocation_size = sys_info.totalram / 20;
 
 	/* Set up test memcg */
-	if (cg_write(root, "cgroup.subtree_control", "+memory"))
-		goto out;
 	test_group = cg_name(root, "kmem_bypass_test");
 	if (!test_group)
 		goto out;