irq_set_irq_wake() treats its second argument as a boolean. It is much
easier to read code when constant booleans are either 0 or 1!

This particular line of code distracted me somewhat when I was doing a bit of
work in a code browser since it (spuriously) got me worried that I had
misunderstood how irq_set_irq_wake() worked.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>