sched: Completely remove CFS_BANDWIDTH support in WALT

Commit I4f3c66a1b567976aadb4a4f91a3dd66230386981 removed support for
CFS_BANDWIDTH, but few stubs are left out. Remove remaining stubs.

Change-Id: I670102fa2efb585106e9c7b60277ff142d64465b
Signed-off-by: Shaleen Agrawal <shalagra@codeaurora.org>