drm/stm: ltdc: check memory returned by devm_kzalloc()

devm_kzalloc() can fail and return NULL pointer. Check its return status.
Identified with Coccinelle (kmerr.cocci script).

Fixes: 484e72d3 ("drm/stm: ltdc: add support of ycbcr pixel formats")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230531072854.142629-1-claudiu.beznea@microchip.comSigned-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>

drivers/gpu/drm/stm/ltdc.c

@@ -1580,6 +1580,8 @@ static struct drm_plane *ltdc_plane_create(struct drm_device *ddev,
 			       ARRAY_SIZE(ltdc_drm_fmt_ycbcr_sp) +
 			       ARRAY_SIZE(ltdc_drm_fmt_ycbcr_fp)) *
 			       sizeof(*formats), GFP_KERNEL);
+	if (!formats)
+		return NULL;
 
 	for (i = 0; i < ldev->caps.pix_fmt_nb; i++) {
 		drm_fmt = ldev->caps.pix_fmt_drm[i];