drm/rockchip: dw_hdmi: add dw-hdmi support for the rk3328

The rk3328 uses a dw-hdmi controller with an external hdmi phy from
Innosilicon which uses the generic phy framework for access.
Add the necessary data and the compatible for the rk3328 to the
rockchip dw-hdmi driver.

changes in v5:
- disable CEC_5V option to make CEC actually work (Jonas)
changes in v3:
- reword as suggested by Rob to show that it's a dw-hdmi + Inno phy

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Zheng Yang <zhengyang@rock-chips.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180912124740.20343-7-heiko@sntech.de