clk: samsung: exynos4415: Fix build with PM_SLEEP disabled

Fix following build errors when PM_SLEEP is disabled (e.g. by disabling
SUSPEND and HIBERNATION):

drivers/clk/samsung/clk-exynos4415.c: In function ‘exynos4415_cmu_init’:
drivers/clk/samsung/clk-exynos4415.c:982:2: error: ‘exynos4415_ctx’ undeclared (first use in this function)
drivers/clk/samsung/clk-exynos4415.c:982:2: note: each undeclared identifier is reported only once for each function it appears in
drivers/clk/samsung/clk-exynos4415.c: In function ‘exynos4415_cmu_dmc_init’:
drivers/clk/samsung/clk-exynos4415.c:1123:2: error: ‘exynos4415_dmc_ctx’ undeclared (first use in this function)
make[3]: *** [drivers/clk/samsung/clk-exynos4415.o] Error 1

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>