mm: memcontrol: drop unused @css argument in memcg_init_kmem

This series adds accounting of the historical "kmem" memory consumers to
the cgroup2 memory controller.

These consumers include the dentry cache, the inode cache, kernel stack
pages, and a few others that are pointed out in patch 7/8.  The
footprint of these consumers is directly tied to userspace activity in
common workloads, and so they have to be part of the minimally viable
configuration in order to present a complete feature to our users.

The cgroup2 interface of the memory controller is far from complete, but
this series, along with the socket memory accounting series, provides
the final semantic changes for the existing memory knobs in the cgroup2
interface, which is scheduled for initial release in the next merge
window.

This patch (of 8):

Remove unused css argument frmo memcg_init_kmem()

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>