genirq/affinity: Move group_cpus_evenly() into lib/

group_cpus_evenly() has become a generic function which can be used for
other subsystems than the interrupt subsystem, so move it into lib/.

Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>                                                                                                                                                                                                    
Link: https://lore.kernel.org/r/[email protected]

Author: Ming Lei

MAINTAINERS

@@ -10935,6 +10935,8 @@ L:	[email protected]
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq/core
 F:	kernel/irq/
+F:	include/linux/group_cpus.h
+F:	lib/group_cpus.c
 
 IRQCHIP DRIVERS
 M:	Thomas Gleixner <[email protected]>

include/linux/group_cpus.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2016 Thomas Gleixner.
+ * Copyright (C) 2016-2017 Christoph Hellwig.
+ */
+
+#ifndef __LINUX_GROUP_CPUS_H
+#define __LINUX_GROUP_CPUS_H
+#include <linux/kernel.h>
+#include <linux/cpu.h>
+
+struct cpumask *group_cpus_evenly(unsigned int numgrps);
+
+#endif