sched/stats: Fix unlikely() use of sched_info_on()

sched_info_on() is called with unlikely hint, however, the test
is to be a constant(1) on which compiler will do nothing when
make defconfig, so remove the hint.

Also, fix a lack of {}.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: up2wing@gmail.com
Cc: wang.liang82@zte.com.cn
Cc: xue.zhihong@zte.com.cn
Link: https://lkml.kernel.org/r/1562301307-43002-1-git-send-email-wang.yi59@zte.com.cn


Signed-off-by: Ingo Molnar <mingo@kernel.org>