defconfig: Enable CPU frequency switch profiling support on Krait targets

CPU frequency switch profiling is by enabled in the regular defconfigs
of msm8974 and apq8084. Enable these for the perf_defconfigs also for
those targets to enable profiling on customer devices.

Change-Id: Iac0add0afa54e6c5a6f69da713c31fd2e20ea0ab
Signed-off-by: Vince Leung <vincentl@codeaurora.org>