RPC: replace Sun license with 3-clause BSD license.

Original commit message:
"Replace Sun RPC license in TI-RPC library with a 3-clause BSD license,
with the explicit permission of Sun Microsystems in 2009."

Taken-from: FreeBSD
Cherry-picked-from: http://svnweb.freebsd.org/base?view=revision&revision=258578
RPC: remove some extraneous $id$ lines.
build - Fix vkernel64 build

* Fix build due to missing declaration from recent commit.
rpc: Remove empty FreeBSD ID.
vkernel64 - Make operational again after bootstrap changes

* vkernel64's need the same cpu_idle_restore() fix that x86-64 got to
  properly handle pending migrations on the BSP at bootstrap time.
  (this occurs due to the way initclocks_other() works now).

* Add a warning/reminder in param.h regarding increasing MAXCPU beyond 256.
drm/i915: Reduce ring code differences with Linux

* Factorize somme common code sequences to __wait_seqno()

* Change locking in get/put irq functions