clk: samsung: exynos4: Use generic helper for handling suspend/resume

Replace common suspend/resume handling code by generic helper.
Handling of PLLs is a bit different in generic code, as they are handled
in the same way as other clock registers. Such approach was already used
on later Exynos SoCs and worked fine. Tests have shown that it works also
on Exynos4 SoCs and significantly simplifies the code.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sylwester Nawrocki <snawrocki@kernel.org>