5045 use atomic_{inc,dec}_* instead of atomic_add_*

@@ -315,11 +315,11 @@
         int i;
         int startidx;
         uchar_t vectmask;
 
         if (irqno <= MAX_ISA_IRQ)
-                atomic_add_16(&uppc_irq_shared_table[irqno], 1);
+                atomic_inc_16(&uppc_irq_shared_table[irqno]);
 
         if (ipl != min_ipl)
                 return (0);
 
         if (irqno > 7) {

@@ -358,11 +358,11 @@
         struct standard_pic *pp;
         int i;
         uchar_t vectmask;
 
         if (irqno <= MAX_ISA_IRQ)
-                atomic_add_16(&uppc_irq_shared_table[irqno], -1);
+                atomic_dec_16(&uppc_irq_shared_table[irqno]);
 
         /*
          * skip if we are not deleting the last handler
          * and the ipl is higher than minimum
          */