drm/tegra: fix potential uninitialized variable use

drm/tegra: fix potential uninitialized variable use

It's likely either output->drm_edid or output->ddc is non-NULL, but
avoid the uninitialized variable usage anyway.

Reported-by: kernel test robot <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/ZtXLyXxew7z6H2bD@stanley.mountain
Fixes: 98365ca74cbf ("drm/tegra: convert to struct drm_edid")
Cc: Thierry Reding <treding@nvidia.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: linux-tegra@vger.kernel.org
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240902161317.2437148-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>