irqchip: bcm2835: Avoid arch/arm-specific handle_IRQ

With commit

  76ba59f8 genirq: Add irq_domain-aware core IRQ handler

architecture-specific irq handlers are no longer necessary.  Update the bcm2835
irq driver to use the core irq handler.  As a bonus, this allows the driver to
support arm64 as well.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Link: https://lkml.kernel.org/r/1464728727-16300-1-git-send-email-eric@anholt.net


[jac reworded commit message for clarity]
Signed-off-by: Jason Cooper <jason@lakedaemon.net>