net: dsa: lantiq_gswip: Exclude RMII from modes that report 1 GbE

Exclude RMII from modes that report 1 GbE support. Reduced MII supports
up to 100 MbE.

Fixes: 14fceff4 ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210107195818.3878-1-olek2@wp.plSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/lantiq_gswip.c

@@ -1436,11 +1436,12 @@ static void gswip_phylink_validate(struct dsa_switch *ds, int port,
 	phylink_set(mask, Pause);
 	phylink_set(mask, Asym_Pause);
 
-	/* With the exclusion of MII and Reverse MII, we support Gigabit,
-	 * including Half duplex
+	/* With the exclusion of MII, Reverse MII and Reduced MII, we
+	 * support Gigabit, including Half duplex
 	 */
 	if (state->interface != PHY_INTERFACE_MODE_MII &&
-	    state->interface != PHY_INTERFACE_MODE_REVMII) {
+	    state->interface != PHY_INTERFACE_MODE_REVMII &&
+	    state->interface != PHY_INTERFACE_MODE_RMII) {
 		phylink_set(mask, 1000baseT_Full);
 		phylink_set(mask, 1000baseT_Half);
 	}