drm/bridge: imx8mp-hdmi-pvi: Fix build warnings

Two separate build warnings were reported.  One from an
uninitialized variable, and the other from returning 0
instead of NULL from a pointer.

Fixes: 059c53e8 ("drm/bridge: imx: add driver for HDMI TX Parallel Video Interface")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402062134.a6CqAt3s-lkp@intel.com/Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240207002305.618499-1-aford173@gmail.comSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240207002305.618499-1-aford173@gmail.com

drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c

@@ -57,7 +57,7 @@ static void imx8mp_hdmi_pvi_bridge_enable(struct drm_bridge *bridge,
 	const struct drm_display_mode *mode;
 	struct drm_crtc_state *crtc_state;
 	struct drm_connector *connector;
-	u32 bus_flags, val;
+	u32 bus_flags = 0, val;
 
 	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
 	conn_state = drm_atomic_get_new_connector_state(state, connector);
@@ -110,7 +110,7 @@ imx8mp_hdmi_pvi_bridge_get_input_bus_fmts(struct drm_bridge *bridge,
 	struct drm_bridge_state *next_state;
 
 	if (!next_bridge->funcs->atomic_get_input_bus_fmts)
-		return 0;
+		return NULL;
 
 	next_state = drm_atomic_get_new_bridge_state(crtc_state->state,
 						     next_bridge);