media: omap2: omapfb: fix ifnullfree.cocci warnings

drivers/video/fbdev/omap2/omapfb/dss/core.c:141:2-26: WARNING: NULL check before some freeing functions is not needed.

 NULL check before some freeing functions is not needed.

 Based on checkpatch warning
 "kfree(NULL) is safe this check is probably not required"
 and kfreeaddr.cocci by Julia Lawall.

Generated by: scripts/coccinelle/free/ifnullfree.cocci
Signed-off-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/video/fbdev/omap2/omapfb/dss/core.c

@@ -137,8 +137,7 @@ static int dss_initialize_debugfs(void)
 
 static void dss_uninitialize_debugfs(void)
 {
-	if (dss_debugfs_dir)
-		debugfs_remove_recursive(dss_debugfs_dir);
+	debugfs_remove_recursive(dss_debugfs_dir);
 }
 
 int dss_debugfs_create_file(const char *name, void (*write)(struct seq_file *))