net: dsa: mv88e6xxx: add port files

The Marvell switches contains one internal SMI device per port, called
"Port Registers". Depending on the model, the addresses of these devices
start from 0x0, 0x8 or 0x10.

Start moving Port Registers specific code to their own files.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 72b9dac2..b32b242 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -37,6 +37,7 @@
 #include "mv88e6xxx.h"
 #include "global1.h"
 #include "global2.h"
+#include "port.h"
 
 static void assert_reg_lock(struct mv88e6xxx_chip *chip)
 {
@@ -221,22 +222,6 @@ int mv88e6xxx_write(struct mv88e6xxx_chip *chip, int addr, int reg, u16 val)
 	return 0;
 }
 
-static int mv88e6xxx_port_read(struct mv88e6xxx_chip *chip, int port, int reg,
-			       u16 *val)
-{
-	int addr = chip->info->port_base_addr + port;
-
-	return mv88e6xxx_read(chip, addr, reg, val);
-}
-
-static int mv88e6xxx_port_write(struct mv88e6xxx_chip *chip, int port, int reg,
-				u16 val)
-{
-	int addr = chip->info->port_base_addr + port;
-
-	return mv88e6xxx_write(chip, addr, reg, val);
-}
-
 static int mv88e6xxx_phy_read(struct mv88e6xxx_chip *chip, int phy,
 			      int reg, u16 *val)
 {