drm/exynos/vidi: fix memory leak in .get_modes()

commit 38e38256 upstream.

The duplicated EDID is never freed. Fix it.

Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>