5255 uts shouldn't open-code ISP2

@@ -335,11 +335,11 @@
         else if (nfreelist < 0 || nfreelist > 4 * max_ncpus) {
                 cmn_err(CE_WARN, "segmap_create: nfreelist out of range "
                 "%d, using %d", nfreelist, max_ncpus);
                 nfreelist = max_ncpus;
         }
-        if (nfreelist & (nfreelist - 1)) {
+        if (!ISP2(nfreelist)) {
                 /* round up nfreelist to the next power of two. */
                 nfreelist = 1 << (highbit(nfreelist));
         }
 
         /*