exynos: Don't depend on DP to set the HDMI clock

exynos: Don't depend on DP to set the HDMI clock

The CONFIG_EXYNOS_DP variable was removed, so this broke. However,
there is no reason we ever depended on DP to pick the HDMI clock,
so get rid of this completely.

TEST=by hand
BUG=chrome-os-partner:14729

Change-Id: Ic6f0267827aea4dc78d005d7bd29b8fe444873ba
Reviewed-on: https://gerrit.chromium.org/gerrit/34432
Tested-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: John Sheu <sheu@chromium.org>
Commit-Ready: Stéphane Marchesin <marcheu@chromium.org>