sched/core: Fix comment typo in wake_q_add()

... the comment clearly refers to wake_up_q(), and not
wake_up_list().

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1462766290-28664-1-git-send-email-dave@stgolabs.net


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