core_ctl: Fix current busy state value in core_ctl_set_busy trace point

core_ctl_set_busy() trace point is supposed to print the busy
state of a CPU in the past and current windows. But this trace
point is called before updating the busy state for the current
window. Fix this issue by moving trace point invocation to
eval_need().

Change-Id: I337a6970e7476766d3b1a5f504c2a524473691bb
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>