clk: samsung: exynos4: Use separate aliases for cpufreq related clocks

Exynos cpufreq driver is the only remaining piece of code that needs
static clkdev aliases for operation, because it can not do device tree
based clock lookups yet.

This patch moves clock alias definitions for those clocks to separate
arrays that can be used with samsung_clk_register_alias() helper.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>