4804 apix & pcplusmp are nearly warning free already
Tentatively Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 551,561 ****
           * use old IPL. Not very elegant, but it should work.
           */
          if ((irqptr->airq_ipl != max_ipl) && (max_ipl != PSM_INVALID_IPL) &&
              !ioapic_mask_workaround[irqptr->airq_ioapicindex]) {
                  apic_irq_t      *irqp;
!                 if (vector = apic_allocate_vector(max_ipl, irqno, 1)) {
                          apic_mark_vector(irqheadptr->airq_vector, vector);
                          irqp = irqheadptr;
                          while (irqp) {
                                  irqp->airq_vector = vector;
                                  irqp->airq_ipl = (uchar_t)max_ipl;
--- 551,561 ----
           * use old IPL. Not very elegant, but it should work.
           */
          if ((irqptr->airq_ipl != max_ipl) && (max_ipl != PSM_INVALID_IPL) &&
              !ioapic_mask_workaround[irqptr->airq_ioapicindex]) {
                  apic_irq_t      *irqp;
!                 if ((vector = apic_allocate_vector(max_ipl, irqno, 1))) {
                          apic_mark_vector(irqheadptr->airq_vector, vector);
                          irqp = irqheadptr;
                          while (irqp) {
                                  irqp->airq_vector = vector;
                                  irqp->airq_ipl = (uchar_t)max_ipl;