External IRQs are currently broken, fix the BCM6345_EXT_IRQ driver.
Since the adoption of the new driver irq-bcm6345-ext, in Chaos Calmer,
external IRQs don't work. It seems there were some minor errors at the initial
development of the driver.
This patch fixes the ticket https://dev.openwrt.org/ticket/21613
Signed-off-by: Daniel Gonzalez <dgcbueu@gmail.com>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>