logind: drop unused user_tasks_max field

We would only write to the field, and take the address. All *readers* were
removed in 2841493927. (The explanation for why
the field wasn't removed back then is that the patch underwent a few iterations,
with the initial version adding translation back and forth. Later versions of
the patch simply emit a warning and ignore the old value. Apparently nobody
noticed that the value became unused.)

src/basic/cgroup-util.h

@@ -129,9 +129,6 @@ static inline bool CGROUP_BLKIO_WEIGHT_IS_OK(uint64_t x) {
             (x >= CGROUP_BLKIO_WEIGHT_MIN && x <= CGROUP_BLKIO_WEIGHT_MAX);
 }
 
-/* Default resource limits */
-#define DEFAULT_USER_TASKS_MAX_PERCENTAGE       33U /* 33% of PIDs, 10813 on default settings */
-
 typedef enum CGroupUnified {
         CGROUP_UNIFIED_UNKNOWN = -1,
         CGROUP_UNIFIED_NONE = 0,        /* Both systemd and controllers on legacy */