net: dsa: mt7530: fix port mirroring for MT7988 SoC switch

The "MT7988A Wi-Fi 7 Generation Router Platform: Datasheet (Open Version)
v0.1" document shows bits 16 to 18 as the MIRROR_PORT field of the CPU
forward control register. Currently, the MT7530 DSA subdriver configures
bits 0 to 2 of the CPU forward control register which breaks the port
mirroring feature for the MT7988 SoC switch.

Fix this by using the MT7531_MIRROR_PORT_GET() and MT7531_MIRROR_PORT_SET()
macros which utilise the correct bits.

Fixes: 110c18bf ("net: dsa: mt7530: introduce driver for MT7988 built-in switch")
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mt7530.c

@@ -1883,14 +1883,16 @@ mt7530_port_vlan_del(struct dsa_switch *ds, int port,
 
 static int mt753x_mirror_port_get(unsigned int id, u32 val)
 {
-	return (id == ID_MT7531) ? MT7531_MIRROR_PORT_GET(val) :
-				   MIRROR_PORT(val);
+	return (id == ID_MT7531 || id == ID_MT7988) ?
+		       MT7531_MIRROR_PORT_GET(val) :
+		       MIRROR_PORT(val);
 }
 
 static int mt753x_mirror_port_set(unsigned int id, u32 val)
 {
-	return (id == ID_MT7531) ? MT7531_MIRROR_PORT_SET(val) :
-				   MIRROR_PORT(val);
+	return (id == ID_MT7531 || id == ID_MT7988) ?
+		       MT7531_MIRROR_PORT_SET(val) :
+		       MIRROR_PORT(val);
 }
 
 static int mt753x_port_mirror_add(struct dsa_switch *ds, int port,