XXXX kmem: remove a check that's always false
It's been a very long time since this code ran on systems with less than
24MB RAM.

*** 4333,4348 ****
          size_t maxverify, minfirewall;
  
          kstat_init();
  
          /*
-          * Small-memory systems (< 24 MB) can't handle kmem_flags overhead.
-          */
-         if (physmem < btop(24 << 20) && !(old_kmem_flags & KMF_STICKY))
-                 kmem_flags = 0;
- 
-         /*
           * Don't do firewalled allocations if the heap is less than 1TB
           * (i.e. on a 32-bit kernel)
           * The resulting VM_NEXTFIT allocations would create too much
           * fragmentation in a small heap.
           */
--- 4333,4342 ----