sched/wait: Clean up some documentation warnings

A couple of kerneldoc comments in <linux/wait.h> had incorrect names for
macro parameters, with this unsightly result:

  ./include/linux/wait.h:555: warning: No description found for parameter 'wq'
  ./include/linux/wait.h:555: warning: Excess function parameter 'wq_head' description in 'wait_event_interruptible_hrtimeout'
  ./include/linux/wait.h:759: warning: No description found for parameter 'wq_head'
  ./include/linux/wait.h:759: warning: Excess function parameter 'wq' description in 'wait_event_killable'

Correct the comments and kill the warnings.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/20170724135800.769c4042@lwn.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/wait.h

@@ -529,13 +529,13 @@ do {										\
 
 /**
  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
- * @wq_head: the waitqueue to wait on
+ * @wq: the waitqueue to wait on
  * @condition: a C expression for the event to wait for
  * @timeout: timeout, as a ktime_t
  *
  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
  * @condition evaluates to true or a signal is received.
- * The @condition is checked each time the waitqueue @wq_head is woken up.
+ * The @condition is checked each time the waitqueue @wq is woken up.
  *
  * wake_up() has to be called after changing any variable that could
  * change the result of the wait condition.
@@ -735,12 +735,12 @@ extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
 
 /**
  * wait_event_killable - sleep until a condition gets true
- * @wq: the waitqueue to wait on
+ * @wq_head: the waitqueue to wait on
  * @condition: a C expression for the event to wait for
  *
  * The process is put to sleep (TASK_KILLABLE) until the
  * @condition evaluates to true or a signal is received.
- * The @condition is checked each time the waitqueue @wq is woken up.
+ * The @condition is checked each time the waitqueue @wq_head is woken up.
  *
  * wake_up() has to be called after changing any variable that could
  * change the result of the wait condition.