video: omapdss: Fix potential null pointer dereference

kmalloc can return null. Add a check to avoid potential null
pointer dereference error when the pointer is accessed later.

Signed-off-by: Sachin Kamat <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/video/fbdev/omap2/dss/omapdss-boot-init.c

···
 {
 	struct dss_conv_node *n = kmalloc(sizeof(struct dss_conv_node),
 		GFP_KERNEL);
-	n->node = node;
-	n->root = root;
-	list_add(&n->list, &dss_conv_list);
+	if (n) {
+		n->node = node;
+		n->root = root;
+		list_add(&n->list, &dss_conv_list);
+	}
 }
 
 static bool __init omapdss_list_contains(const struct device_node *node)