5255 uts shouldn't open-code ISP2

@@ -908,11 +908,11 @@
 
         /*
          * contig_mem_alloc requires size to be a power of 2.
          * Increase size to next power of 2 if necessary.
          */
-        if ((pri_size & (pri_size - 1)) != 0)
+        if (!ISP2(pri_size))
                 buf_size = 1 << highbit(pri_size);
         DS_PRI_DBG("ds_get_hv_pri: buf_size = 0x%lx\n", buf_size);
 
         buf_va = contig_mem_alloc(buf_size);
         if (buf_va == NULL)