Fix issues brought up by Nathan's assertify patch for the ia64 backend.

Fix issues brought up by Nathan's assertify patch for the ia64 backend.

* config/ia64/ia64.c (update_set_flags): Delete ppred and pcond
parameters.  Replace conditional move code with assert checking for
ar.lc.  Delete obsolete comments.
(set_src_needs_barrier): Delete cond parameter, and code using it.
(rtx_needs_barrier): Delete initialization of cond.  Fix typo in
assert checking for PR_REGS.  Fix calls to update_set_flags and
set_src_needs_barrier.
(group_barrier_needed): Renamed from group_barrier_needed_p.  Fix all
callers.  Rewrite explanatory comment before the function.
(safe_group_barrier_needed): Renamed from safe_group_barrier_needed_p.
Fix all callers.

From-SVN: r98900