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

commit 38e3825631b1f314b21e3ade00b5a4d737eb054e 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>