sched/docbook: Fix 'make htmldocs' warnings caused by missing description

When 'flags' argument to sched_{set,get}attr() syscalls were
added in:

  6d35ab48090b ("sched: Add 'flags' argument to sched_{set,get}attr() syscalls")

no description for 'flags' was added. It causes the following warnings on "make htmldocs":

  Warning(/kernel/sched/core.c:3645): No description found for parameter 'flags'
  Warning(/kernel/sched/core.c:3789): No description found for parameter 'flags'

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1397753955-2914-1-git-send-email-standby24x7@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -3639,6 +3639,7 @@ SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
  * sys_sched_setattr - same as above, but with extended sched_attr
  * @pid: the pid in question.
  * @uattr: structure containing the extended parameters.
+ * @flags: for future extension.
  */
 SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
 			       unsigned int, flags)
@@ -3783,6 +3784,7 @@ err_size:
  * @pid: the pid in question.
  * @uattr: structure containing the extended parameters.
  * @size: sizeof(attr) for fwd/bwd comp.
+ * @flags: for future extension.
  */
 SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
 		unsigned int, size, unsigned int, flags)