ARM: exynos_defconfig: Enable Samsung media platform drivers as modules

ARM: exynos_defconfig: Enable Samsung media platform drivers as modules

There are a bunch of media platform drivers under drivers/media/platform/
that are for Samsung SoCs but are not being built with exynos_defconfig.

This patch enables them as a module to improve build coverage for these
drivers and also to allow people use them with proper hardware if modules
are installed. The S5P MFC driver wasn't enabled since it fails to probe.

Only the boolean Kconfig symbols are enabled as built-in, since drivers
are not critical and also to keep the kernel binary image size as small
as possible.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>