sched/walt: Remove dependency on sd_asym_cpucapacity for task placement

We have a separate implementation of find_energy_efficient_cpu() for
WALT. The task placement rely on CPU arrays and WALT load signals.
Hence remove sd_asym_cpucapacity checks and updates to PELT signals
from find_energy_efficient_cpu().

Change-Id: I20a186e7a10d1ab6ee5f502f5dbf2de14d7971d5
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>