net: pcs: xpcs: remove return statements in void function

While using "return" when calling a void returning function inside a
function that returns void doesn't cause a compiler warning, it looks
weird. Convert the bunch of if() statements to a switch() and remove
these return statements.

Signed-off-by: Russell King (Oracle) <[e-mail]>
Tested-by: Serge Semin <[e-mail]>
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/pcs/pcs-xpcs.c

···
 {
 	struct dw_xpcs *xpcs = phylink_pcs_to_xpcs(pcs);
 
-	if (interface == PHY_INTERFACE_MODE_USXGMII)
-		return xpcs_link_up_usxgmii(xpcs, speed);
+	switch (interface) {
+	case PHY_INTERFACE_MODE_USXGMII:
+		xpcs_link_up_usxgmii(xpcs, speed);
+		break;
 
-	if (interface == PHY_INTERFACE_MODE_SGMII ||
-	    interface == PHY_INTERFACE_MODE_1000BASEX)
-		return xpcs_link_up_sgmii_1000basex(xpcs, neg_mode, interface,
-						    speed, duplex);
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+		xpcs_link_up_sgmii_1000basex(xpcs, neg_mode, interface, speed,
+					     duplex);
+		break;
+
+	default:
+		break;
+	}
 }
 
 static void xpcs_an_restart(struct phylink_pcs *pcs)