drivers/net: Fix ptr_ret.cocci warnings.

we can use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR
1. drivers/net/appletalk/ipddp.c
2. drivers/net/wireless/broadcom/brcm80211/brcmfmac/debug.c

Generated by: scripts/coccinelle/api/ptr_ret.cocci
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/appletalk/ipddp.c

@@ -311,9 +311,7 @@ module_param(ipddp_mode, int, 0);
 static int __init ipddp_init_module(void)
 {
 	dev_ipddp = ipddp_init();
-        if (IS_ERR(dev_ipddp))
-                return PTR_ERR(dev_ipddp);
-	return 0;
+	return PTR_ERR_OR_ZERO(dev_ipddp);
 }
 
 static void __exit ipddp_cleanup_module(void)

drivers/net/wireless/broadcom/brcm80211/brcmfmac/debug.c

@@ -78,10 +78,7 @@ int brcmf_debug_attach(struct brcmf_pub *drvr)
 		return -ENODEV;
 
 	drvr->dbgfs_dir = debugfs_create_dir(dev_name(dev), root_folder);
-	if (IS_ERR(drvr->dbgfs_dir))
-		return PTR_ERR(drvr->dbgfs_dir);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(drvr->dbgfs_dir);
 }
 
 void brcmf_debug_detach(struct brcmf_pub *drvr)