clk: samsung: Remove double assignment of CLK_ARM_CLK in Exynos4 driver

CLK_ARM_CLK ("armclk") clock is provided by cpu-clk subdriver, which is
instantiated after creating all divider clocks from exynos4_div_clks
array. There is no point assigning this id to "div_core2" clock and later
overwrite with proper "armcpu" clock by cpu-clk subdriver.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>