drm/exynos: Make exynos4/5_fimd_driver_data static

Fixes the following sparse warnings:
drivers/gpu/drm/exynos/exynos_drm_fimd.c:65:25: warning:
symbol 'exynos4_fimd_driver_data' was not declared. Should it be static?
drivers/gpu/drm/exynos/exynos_drm_fimd.c:69:25: warning:
symbol 'exynos5_fimd_driver_data' was not declared. Should it be static?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -61,11 +61,11 @@ struct fimd_driver_data {
 	unsigned int timing_base;
 };
 
-struct fimd_driver_data exynos4_fimd_driver_data = {
+static struct fimd_driver_data exynos4_fimd_driver_data = {
 	.timing_base = 0x0,
 };
 
-struct fimd_driver_data exynos5_fimd_driver_data = {
+static struct fimd_driver_data exynos5_fimd_driver_data = {
 	.timing_base = 0x20000,
 };