selftests: cgroup: Make cg_create() use 0755 for permission instead of 0644

stable inclusion
from stable-v5.10.111
commit 9dd39d2c6572c7be091ecd6aced950bd91175415
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5GL1Z

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9dd39d2c6572c7be091ecd6aced950bd91175415



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commit b09c2baa upstream.

0644 is an odd perm to create a cgroup which is a directory. Use the regular
0755 instead. This is necessary for euid switching test case.

Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>