net: dsa: make the STP state function return void

The DSA layer doesn't care about the return code of the port_stp_update
routine, so make it void in the layer and the DSA drivers.

Replace the useless dsa_slave_stp_update function with a
dsa_slave_stp_state function used to reply to the switchdev
SWITCHDEV_ATTR_ID_PORT_STP_STATE attribute.

In the meantime, rename port_stp_update to port_stp_state_set to
explicit the state change.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/bcm_sf2.c b/drivers/net/dsa/bcm_sf2.c
index 95944d5..2bba1d9 100644
--- a/drivers/net/dsa/bcm_sf2.c
+++ b/drivers/net/dsa/bcm_sf2.c
@@ -545,12 +545,11 @@
 	priv->port_sts[port].bridge_dev = NULL;
 }
 
-static int bcm_sf2_sw_br_set_stp_state(struct dsa_switch *ds, int port,
-				       u8 state)
+static void bcm_sf2_sw_br_set_stp_state(struct dsa_switch *ds, int port,
+					u8 state)
 {
 	struct bcm_sf2_priv *priv = ds_to_priv(ds);
 	u8 hw_state, cur_hw_state;
-	int ret = 0;
 	u32 reg;
 
 	reg = core_readl(priv, CORE_G_PCTL_PORT(port));
@@ -574,7 +573,7 @@
 		break;
 	default:
 		pr_err("%s: invalid STP state: %d\n", __func__, state);
-		return -EINVAL;
+		return;
 	}
 
 	/* Fast-age ARL entries if we are moving a port from Learning or
@@ -584,10 +583,9 @@
 	if (cur_hw_state != hw_state) {
 		if (cur_hw_state >= G_MISTP_LEARN_STATE &&
 		    hw_state <= G_MISTP_LISTEN_STATE) {
-			ret = bcm_sf2_sw_fast_age_port(ds, port);
-			if (ret) {
+			if (bcm_sf2_sw_fast_age_port(ds, port)) {
 				pr_err("%s: fast-ageing failed\n", __func__);
-				return ret;
+				return;
 			}
 		}
 	}
@@ -596,8 +594,6 @@
 	reg &= ~(G_MISTP_STATE_MASK << G_MISTP_STATE_SHIFT);
 	reg |= hw_state;
 	core_writel(priv, reg, CORE_G_PCTL_PORT(port));
-
-	return 0;
 }
 
 /* Address Resolution Logic routines */
@@ -1387,7 +1383,7 @@
 	.set_eee		= bcm_sf2_sw_set_eee,
 	.port_bridge_join	= bcm_sf2_sw_br_join,
 	.port_bridge_leave	= bcm_sf2_sw_br_leave,
-	.port_stp_update	= bcm_sf2_sw_br_set_stp_state,
+	.port_stp_state_set	= bcm_sf2_sw_br_set_stp_state,
 	.port_fdb_prepare	= bcm_sf2_sw_fdb_prepare,
 	.port_fdb_add		= bcm_sf2_sw_fdb_add,
 	.port_fdb_del		= bcm_sf2_sw_fdb_del,