net: dsa: microchip: ksz8795: remove unused last_port variable

The variable last_port is not used anywhere, this patch removes it.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz8795.c

@@ -1163,7 +1163,6 @@ static int ksz8795_switch_detect(struct ksz_device *dev)
 			id2 = 0x65;
 	} else if (id2 == CHIP_ID_94) {
 		dev->port_cnt--;
-		dev->last_port = dev->port_cnt;
 		id2 = 0x94;
 	}
 	id16 &= ~0xff;

drivers/net/dsa/microchip/ksz_common.h

@@ -72,7 +72,6 @@ struct ksz_device {
 	int reg_mib_cnt;
 	int mib_cnt;
 	int mib_port_cnt;
-	int last_port;			/* ports after that not used */
 	phy_interface_t compat_interface;
 	u32 regs_size;
 	bool phy_errata_9477;