Use tabs instead of spaces for indentation

This completes our switch to the Linux kernel coding style. Note that we
still use deeply nested constructs at some places which need to be fixed
up later.

Converted using the `Lindent` script from the Linux kernel code base,
along with some manual fixes.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/llist.h

@@ -37,14 +37,14 @@
 /* Linked lists. */
 typedef struct llist_item llist_item_t;
 struct llist_item {
-  struct llist_item *next;
-  void *data;
+	struct llist_item *next;
+	void *data;
 };
 
 typedef struct llist llist_t;
 struct llist {
-  struct llist_item *head;
-  struct llist_item *tail;
+	struct llist_item *head;
+	struct llist_item *tail;
 };
 
 typedef int (*llist_fn_cmp_t) (void *, void *);