drm: bridge: dw-hdmi: Handle overflow workaround based on device version

Use the device version queried at runtime instead of the device type
provided through platform data to handle the overflow workaround. This
will make support of other SoCs integrating the same HDMI TX controller
version easier.

Among the supported platforms only i.MX6DL and i.MX6Q have been
identified as needing the workaround. Disabling it on Rockchip RK3288
(which integrates a v2.00a controller) didn't produce any error or
artifact.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170117082910.27023-16-laurent.pinchart+renesas@ideasonboard.com