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: 98365ca7 ("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.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 8e514bad271723473d31fcc496f7143ba49c43c5)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

drivers/gpu/drm/tegra/output.c

@@ -21,7 +21,7 @@
 int tegra_output_connector_get_modes(struct drm_connector *connector)
 {
 	struct tegra_output *output = connector_to_output(connector);
-	const struct drm_edid *drm_edid;
+	const struct drm_edid *drm_edid = NULL;
 	int err = 0;
 
 	/*