HSI: omap_ssi: Fix return value check in ssi_debug_add_ctrl()

In case of error, the function debugfs_create_*() returns NULL
pointer not ERR_PTR() if debugfs is enabled. The IS_ERR() test
in the return value check should be replaced with NULL test.

Signed-off-by: Wei Yongjun <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/hsi/controllers/omap_ssi.c

···
 
 	/* SSI controller */
 	omap_ssi->dir = debugfs_create_dir(dev_name(&ssi->device), NULL);
-	if (IS_ERR(omap_ssi->dir))
-		return PTR_ERR(omap_ssi->dir);
+	if (!omap_ssi->dir)
+		return -ENOMEM;
 
 	debugfs_create_file("regs", S_IRUGO, omap_ssi->dir, ssi,
 								&ssi_regs_fops);
 	/* SSI GDD (DMA) */
 	dir = debugfs_create_dir("gdd", omap_ssi->dir);
-	if (IS_ERR(dir))
+	if (!dir)
 		goto rback;
 	debugfs_create_file("regs", S_IRUGO, dir, ssi, &ssi_gdd_regs_fops);
 
···
 rback:
 	debugfs_remove_recursive(omap_ssi->dir);
 
-	return PTR_ERR(dir);
+	return -ENOMEM;
 }
 
 static void ssi_debug_remove_ctrl(struct hsi_controller *ssi)