media: sec: Remove PLAT_S5P dependency

The PLAT_S5P symbol was removed in commit d78c16cc ("ARM: SAMSUNG:
Remove remaining legacy code").

Remove the PLAT_S5P dependency from VIDEO_SAMSUNG_S5P_CEC.

Discovered with the
https://github.com/ulfalizer/Kconfiglib/blob/master/examples/list_undefined.py
script.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/Kconfig

@@ -591,7 +591,7 @@ config CEC_GPIO
 
 config VIDEO_SAMSUNG_S5P_CEC
        tristate "Samsung S5P CEC driver"
-       depends on PLAT_S5P || ARCH_EXYNOS || COMPILE_TEST
+       depends on ARCH_EXYNOS || COMPILE_TEST
        select CEC_CORE
        select CEC_NOTIFIER
        ---help---