rcu: Change function declaration to bool

Author: Nicholas Mc Guire <hofrat@osadl.org>

rcu_cpu_has_callbacks() is declared int. The current declaration was introduced
in commit c0f4dfd4f90f (rcu: Make RCU_FAST_NO_HZ take advantage of numbered
callbacks). But it is actually returning bool and as the function description
states " * Return true if the specified CPU has any callback....", this probably
should be a bool as all (3) call-sites currently treat it as bool.

Type-checking coccinelle spatches are being used to locate type mismatches
between function signatures and return values in this case this produced:
./kernel/rcu/tree.c:3538 WARNING: return of wrong type
                    int != bool,

Patch was compile tested with x86_64_defconfig (implies CONFIG_TREE_RCU=y)

Patch is against 4.1-rc3 (localversion-next is -next-20150511) and fixes

Signed-off-by: Nicholas Mc Guire 
Reviewed-by: Josh Triplett 
Signed-off-by: Paul E. McKenney 

---
 kernel/rcu/tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 6efb0b6..7b9dd4f 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3496,7 +3496,7 @@ static int rcu_pending(void)
  * non-NULL, store an indication of whether all callbacks are lazy.
  * (If there are no callbacks, all of them are deemed to be lazy.)
  */
-static int __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
+static bool __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
 {
 	bool al = true;
 	bool hc = false;