Use fatbit for anch log, delay slots in scratch

Since these structures are in scratch, they do not have to be as small
as possible and we can use fatbit instead of multibit to improve
performance.

src/util/fatbit.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, Intel Corporation
+ * Copyright (c) 2015-2016, Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -58,21 +58,25 @@ void fatbit_clear(struct fatbit *bits) {
 
 static really_inline
 char fatbit_set(struct fatbit *bits, u32 total_bits, u32 key) {
+    assert(ISALIGNED(bits));
     return mmbit_set(bits->fb_int.raw, total_bits, key);
 }
 
 static really_inline
 void fatbit_unset(struct fatbit *bits, u32 total_bits, u32 key) {
+    assert(ISALIGNED(bits));
      mmbit_unset(bits->fb_int.raw, total_bits, key);
 }
 
 static really_inline
 char fatbit_isset(const struct fatbit *bits, u32 total_bits, u32 key) {
+    assert(ISALIGNED(bits));
     return mmbit_isset(bits->fb_int.raw, total_bits, key);
 }
 
 static really_inline
 u32 fatbit_iterate(const struct fatbit *bits, u32 total_bits, u32 it_in) {
+    assert(ISALIGNED(bits));
     /* TODO: iterate_flat could be specialised as we don't have to worry about
      * partial blocks. */
     return mmbit_iterate(bits->fb_int.raw, total_bits, it_in);