dt-bindings: memory-controllers: exynos5422-dmc: Correct example syntax and memory region

After adding the interrupt properties to Exynos5422 DMC bindings
example, the mapped memory region must be big enough to access
performance counters registers.

Fix also syntax errors (semicolons) and adjust indentation.

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