kernel -- ffs: Softdep lock and assorted fixes
* Remove interlocked_sleep; we can just use lksleep directly
* sema_get no longer eats the interlock passed in; all of its
callers were retaking the lock eventually or immediately.
* softdep was setting up a callout to wake itself in request_cleanup.
Switch to directly using timeout in lksleep for this purpose.
* Do not access inodedep structure outside of softdep lock in
softdep_update_inodeblock for buffer field.
* Remove prio field from semaphores; they were unused and the DFly
tsleep routines do not respect priority anyway.
* Do not release softdep lock before panic()ing