sched/core: fix userspace affining threads incorrectly

Certain userspace applications, to achieve max performance, affines its
threads to cpus that run the fastest. This is not always the
correct strategy. For e.g. in certain architectures all the
cores have the same max freq but few of them have a bigger
cache. Affining to the cpus that have bigger cache is advantageous
but such an application would end up affining them to all the cores.
Similarly if an architecture has just one cpu that runs at max freq,
it ends up crowding all its thread on that single core, which is
detrimental for performance.

To address this issue, we need to detect a suspicious looking affinity
request from userspace and check if it links in a particular library.
The latter can easily be detected by traversing executable vm areas
that map a file and checking for that library name.
When such a affinity request is found, change it to use a proper
affinity. The suspicious affinity request, the proper affinity request
and the library name can be configured by the userspace.

Change-Id: I6bb8c310ca54c03261cc721f28dfd6023ab5591a
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>