BFQ: Change elevator_type to type

Fixes the following compile error:
kernel/amazon/otter-common/block/bfq-cgroup.c: In function 'bfq_cic_change_cgroup':
kernel/amazon/otter-common/block/bfq-cgroup.c:346:36: error: 'struct elevator_queue' has no member named 'elevator_type'

See also "block: remove elevator_queue->ops"
https://github.com/loosethisskin/kernel_omap/commit/29b7005143327edd8f6fc2647d161f8b7655095f