drm/exynos: hdmi: Use drm_display_mode to set registers

drm/exynos: hdmi: Use drm_display_mode to set registers

Program the core and timing generator registers using the timing data
provided in drm_display_mode instead of using hardcoded configurations.
This allows us to support more than just 4 video modes.

Due to lack of definition in the datasheet, this patch removes
interlaced mode support for the timing being.

BUG=chrome-os-partner:11790
TEST=Tested on snow using a Samsung panel

Change-Id: I1d8c27c837a38a4b095993c7f029c5374631995c
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/29956