irqchip/bcm-6345-l1: Report that effective affinity is a single target

The BCM 6345-L1 driver only targets a single CPU at a time, even if
the notional affinity is wider. Let's inform the core code
about this.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Link: http://lkml.kernel.org/r/20170818083925.10108-8-marc.zyngier@arm.com

drivers/irqchip/Kconfig

@@ -96,6 +96,7 @@ config BCM6345_L1_IRQ
 	bool
 	select GENERIC_IRQ_CHIP
 	select IRQ_DOMAIN
+	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
 
 config BCM7038_L1_IRQ
 	bool