The bcm6345-periph-intc driver only targets a single CPU at a time, even
if the notional affinity is wider. Let's inform the core code about this.
This patch gets rid of the kernel message:
"genirq: irq_chip bcm6345-periph-intc did not update eff. affinity mask
of irq 52"
Signed-off-by: Daniel Gonzalez Cabanelas <dgcbueu@gmail.com>