clk: samsung: Remove support for obsolete Exynos4212 CPU clock

Support for Exynos 4212 SoC has been removed by commit bca9085e ("ARM:
dts: exynos: remove Exynos4212 support (dead code)"), so there is no need
to keep dead code.

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