clk: samsung: add needed IDs for DMC clocks in Exynos5420

Define new IDs for clocks used by Dynamic Memory Controller in
Exynos5422 SoC.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>