sched: remove the unused HMP specific code

Remove the unused HMP specific code, mostly wrappers used in
load balancer and task placement. The CFS_BANDWIDTH feature is
supported for HMP but not for WALT. So remove any remaining
references to this feature. It will be reintroduced for WALT
in the subsequent patches.

Change-Id: Ic166b5e0f2abc0060c5030784c4ff22efc0e3885
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>