drm/exynos: add HDMI version 1.4 support

Later Exynos series from Exynos4X12 support HDMI version 1.4. We will
distinguish to use which version via platform data. This patch supports
only default features of HDMI version 1.4(The 3D, sound and etc don't
support yet)

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>