IB/ipath: Convert old cpumask api into new one

Adapt to new api.  We plan to remove old one later.  Almost all
changes are trivial, but there is one real fix: the following code is
unsafe:

	int ncpus = num_online_cpus()
	for (i = 0; i < ncpus; i++) {
		..
	}

because 1) we don't guarantee last bit of online cpus is equal to
num_online_cpus(). some arch assign sparse cpu number.  2) cpu
hotplugging may change cpu_online_mask at same time.  we need to pin
it by get_online_cpus().

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>