ARM: dts: exynos: Add DMC device to Exynos5422 and Odroid XU3-family boards

Add description of Dynamic Memory Controller and PPMU counters to
Exynos5422 and Odroid XU3/XU4/HC1 boards.  They are used by
exynos5422-dmc driver.  There is a definition of the memory chip, which
is then used during calculation of timings for each OPP.
The algorithm in the driver needs these two sets to bound the timings.

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