sched: fix signedness warnings in sched.c

Unsigned long values are always assigned to switch_count,
make it unsigned long.

kernel/sched.c:3897:15: warning: incorrect type in assignment (different signedness)
kernel/sched.c:3897:15:    expected long *switch_count
kernel/sched.c:3897:15:    got unsigned long *<noident>
kernel/sched.c:3921:16: warning: incorrect type in assignment (different signedness)
kernel/sched.c:3921:16:    expected long *switch_count
kernel/sched.c:3921:16:    got unsigned long *<noident>

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 7286ccb..f06950c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3889,7 +3889,7 @@
 asmlinkage void __sched schedule(void)
 {
 	struct task_struct *prev, *next;
-	long *switch_count;
+	unsigned long *switch_count;
 	struct rq *rq;
 	int cpu;