[media] exynos4-is: Add support for all required clocks

This patch adds 3 more clocks to Exynos4 ISP driver. Enabling them is
needed to make the hardware operational. Till now it worked only because
those clocks were registered with IGNORE_UNUSED flag and were enabled
by default after SoC reset.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>