drm/exynos: add new compatible strings for hdmi subsystem

This patch adds new combatible strings for hdmi, mixer, ddc
and hdmiphy. It follows the convention of using compatible string
which represent the SoC in which the IP was added for the first
time.

Drivers continue to support the previous compatible strings
but further addition of these compatible strings in device tree
is deprecated.

Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>