defconfig: msm8994-perf: enable CONFIG_SCHED_DEBUG

The SCHED_DEBUG feature causes useful scheduler information to be
made available at /proc/sched_debug. It does not have any noticeable
performance impact.

Change-Id: I4ff78b92d58f09cc8f28d8b765c1369fb64249dc
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>