net: dsa: mt7530: do not clear config->supported_interfaces

There's no need to clear the config->supported_interfaces bitmap before
reporting the supported interfaces as all bits in the bitmap will already
be initialized to zero when the phylink_config structure is allocated. The
"config" pointer points to &dp->phylink_config, and "dp" is allocated by
dsa_port_touch() with kzalloc(), so all its fields are filled with zeroes.

There's no code that would change the bitmap beforehand. Remove it.

Acked-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Link: https://lore.kernel.org/r/20240206-for-netnext-mt7530-improvements-2-v5-7-d7d92a185cb1@arinc9.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/mt7530.c

@@ -2573,8 +2573,6 @@ static void mt7531_mac_port_get_caps(struct dsa_switch *ds, int port,
 static void mt7988_mac_port_get_caps(struct dsa_switch *ds, int port,
 				     struct phylink_config *config)
 {
-	phy_interface_zero(config->supported_interfaces);
-
 	switch (port) {
 	/* Ports which are connected to switch PHYs. There is no MII pinout. */
 	case 0 ... 3: