The original arm code has a pr_debug() statement for the case where
the irq chip has no set_affinity() callback. That's sufficient for
debugging and we really don't want to spam dmesg with useless warnings
for the normal case.

Fixes: f1e0bb0ad473: "genirq: Introduce generic irq migration for cpu hotunplug"
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Requested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>

ARM and ARM64 have almost identical code for migrating interrupts on
cpu hotunplug. Provide a generic version which can be used by both.

The new code addresses a shortcoming in the ARM[64] variants which
fails to update the affinity change in some cases. The solution for
this is to use the core function irq_do_set_affinity() instead of open
coding it.

[ tglx: Added copyright notice and license boilerplate. Rewrote
  	subject and changelog. ]

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: <linux-arm-kernel@lists.infradead.org>
Link: http://lkml.kernel.org/r/1443087135-17044-2-git-send-email-yangyingliang@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>