ipvs: fix the remaining sparse warnings in ip_vs_ctl.c

- RCU annotations for ip_vs_info_seq_start and _stop
- __percpu for cpustats
- properly dereference svc->pe in ip_vs_genl_fill_service

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>