cgroup: bpf: use cgroup_lock()/cgroup_unlock() wrappers

[ Upstream commit 4cdb91b0 ]

Replace mutex_[un]lock() with cgroup_[un]lock() wrappers to stay
consistent across cgroup core and other subsystem code, while
operating on the cgroup_mutex.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Stable-dep-of: 2bd11033 ("cgroup: always put cset in cgroup_css_set_put_fork")
Signed-off-by: Sasha Levin <sashal@kernel.org>