ARM: dts: exynos: Add interrupts to DMC controller in Exynos5422

Add interrupts to Dynamic Memory Controller in Exynos5422 and Odroid
XU3-family boards. It will be used instead of devfreq polling mode
governor. The interrupt is connected to performance counters private
for DMC, which might track utilisation of the memory channels.

Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>