Prioritize requests based on cpu boosting level

Prioritize requests based on cpu boosting level

There are three boosting levels at present, hence three distinct
priorities are introduced. Since the priority space is small, the
priority queue is implemented via an array of FIFO queues.

CPU priority inheritance from client to server is also included.

The boosting level and priority inheritance facilities are provided by
the capi-system-resource module. According to said facilities'
designers, querying the boosting level is most efficient when done
directly in the queried thread. Thus, when making a security manager
client request, the boosting level is obtained and prepended to the
request payload. This is also makes requests atomic and mitigates the
potential for priority races.

Change-Id: Icc10fb5e40fa74eafe16726d28ac66cd8b560810