clk: samsung: exynos5420: Add clock IDs needed by GPU

Adds IDs for the clocks needed by the ARM Mali GPU
in exynos5420.

Signed-off-by: Arun Kumar K <arun.kk@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>

diff --cc drivers/clk/samsung/clk-exynos5420.c
Simple merge

diff --cc include/dt-bindings/clock/exynos5420.h
Simple merge