trusty: add support for parameterized NOP ops

Parameterized NOPs are introduced by Trusty secure side to
facilitate better SMP concurrency. They are effectively NOP
calls with parameters that will be routed to appropriate
handlers on secure side which can be executed concurrently
on multiple CPUs. Parameterized NOPs are represented by
trusty_nop structure that has to be initialized by calling
trusty_nop_init call. This patch creates queue for such items,
adds per CPU work queue to invoke them and adds API to enqueue
and dequeue them.

Change-Id: I4c450c3d6cc18b246dfd0ca4526ef8703c1c2d64
Signed-off-by: Michael Ryleev <gmar@google.com>