ARM: Dove: Add RTC interrupt via PMU interrupt controller.

The RTC on Dove has an interrupt on the PMU interrupt controller.
Add this interrupt to the RTC node. Tested using the
"RTC Driver Test Example"

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>