sched: Provide a wake up API without sending freq notifications

Each time a task wakes up, scheduler evaluates its load and notifies
governor if the resulting frequency of destination CPU is larger than
a threshold. However, some governor wakes up a separate task that
handles frequency change, which again calls wake_up_process().

This is dangerous because if the task being woken up meets the
threshold and ends up being moved around, there is a potential for
endless recursive notifications.

Introduce a new API for waking up a task without triggering
frequency notification.

Change-Id: I24261af81b7dc410c7fb01eaa90920b8d66fbd2a
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>