genirq/affinity: Pass first vector to __irq_build_affinity_masks()

genirq/affinity: Pass first vector to __irq_build_affinity_masks()

No functional change.

Prepares for support of allocating and affinitizing sets of interrupts, in
which each set of interrupts needs a full two stage spreading. The first
vector argument is necessary for this so the affinitizing starts from the
first vector of each set.

[ tglx: Minor changelog tweaks ]

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: Hannes Reinecke <hare@suse.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Link: https://lkml.kernel.org/r/20181102145951.31979-4-ming.lei@redhat.com