kernel - Hold required token when accessing p_flags, adjust kmem access

kernel - Hold required token when accessing p_flags, adjust kmem access

* Numerous adjustments to p->p_flag were not being done with p->p_token held.
  In particular uiomove().

* Replace P_DEADLKTREAT with LWP_DEADLKTREAT in several places where it had
  not been previously converted.

* Allow DMAP access in is_globaldata_space() for x86-64