sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>

It's used only by a single (rarely used) inline function (task_node(p)),
which we can move to <linux/sched/topology.h>.

( Add <linux/nodemask.h>, because we rely on that. )

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched.h

@@ -4,6 +4,7 @@
 #include <uapi/linux/sched.h>
 
 #include <linux/sched/prio.h>
+#include <linux/nodemask.h>
 
 #include <linux/mutex.h>
 #include <linux/plist.h>
@@ -21,7 +22,6 @@
 #include <linux/kcov.h>
 #include <linux/task_io_accounting.h>
 #include <linux/latencytop.h>
-#include <linux/topology.h>
 
 #include <asm/current.h>
 
@@ -1454,11 +1454,6 @@ static inline unsigned int task_cpu(const struct task_struct *p)
 #endif
 }
 
-static inline int task_node(const struct task_struct *p)
-{
-	return cpu_to_node(task_cpu(p));
-}
-
 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
 
 #else