IB/ipath: Fix unit selection when all CPU affinity bits set

At some point things changed so that all the affinity bits can be set,
but cpus_full() macro is not true.  This caused problems with the unit
selection logic on multi-unit (board) configurations.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>