[media] exynos4-is: Compile in fimc runtime PM callbacks conditionally
Enclose the runtime PM helpers in #ifdef CONFIG_PM_RUNTIME/#endif
to avoid following compile warning when CONFIG_PM_RUNTIME is disabled:
CC drivers/media/platform/exynos4-is/fimc-core.o
drivers/media/platform/exynos4-is/fimc-core.c:1040:12: warning: ‘fimc_runtime_resume’ defined but not used
drivers/media/platform/exynos4-is/fimc-core.c:1057:12: warning: ‘fimc_runtime_suspend’ defined but not used