cgroup2: switch to option-by-option parsing

[again, carved out of patch by dhowells]
[NB: we probably want to handle "source" in parse_param here]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2019-01-17 00:22:58 -05:00
commit e34a98d5b2