[media] s5p-g2d: remove non-device-tree init code

Exynos and Samsung S5P platforms has been fully converted to device
tree, so old platform device based init data can be now removed.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>