sched/fair: Remove a duplicate trace print

If the FBT takes the fast path for prev_cpu, a duplicate trace_print
would occur and shares no additional information. Clean this addtional
trace_print.

Change-Id: I3257ffab03b6ba27bec226609b553ff25297e513
Signed-off-by: Runmin Wang <runminw@codeaurora.org>