[PATCH] timers/nohz: fix implicit dependency on "struct rq"

[Paul Gortmaker <paul.gortmaker@windriver.com>]

Backports to older v5.x kernels revealed a recently introduced
implicit dependency on struct rq that makes the nohz.h header
no longer stand alone.  This is most easily demonstrated as:

   $ echo '#include <linux/sched/nohz.h>' > init/main.c
   $ echo 'void foo(void) {}' >> init/main.c
   $ make init/main.o
     CC      init/main.o
   In file included from init/main.c:1:0:
   ./include/linux/sched/nohz.h:18:35: warning: ‘struct rq’ declared inside parameter list [enabled by default]
    void calc_load_nohz_remote(struct rq *rq);
                                      ^
   ./include/linux/sched/nohz.h:18:35: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]

Fixes: ebc0f83c78a2 ("timers/nohz: Update NOHZ load in remote tick")
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 include/linux/sched/nohz.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/sched/nohz.h b/include/linux/sched/nohz.h
index 6d67e9a5af6b..67a105b3dd82 100644
--- a/include/linux/sched/nohz.h
+++ b/include/linux/sched/nohz.h
@@ -6,6 +6,8 @@
  * This is the interface between the scheduler and nohz/dynticks:
  */
 
+struct rq;
+
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 extern void nohz_balance_enter_idle(int cpu);
 extern int get_nohz_timer_target(void);
-- 
1.9.1