IB/qib: Convert old cpumask api into new one

Adapt to use new APIs.  We plan to remove old one later and plan to
change current->cpus_allowed implementation.

No functional change.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>