net: dsa: microchip: ksz9477: remove MII_CTRL1000 check from ksz9477_w_phy()

The reason why PHYlib may access MII_CTRL1000 on the chip without GBit
support is only if chip provides wrong information about extended caps
register. This issue is now handled by ksz9477_r_phy_quirks()

With proper regmap_ranges provided for all chips we will be able to
catch this kind of bugs any way. So, remove this sanity check.
Signed-off-by: NOleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: NVladimir Oltean <olteanv@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/ksz9477.c

@@ -341,10 +341,6 @@ int ksz9477_w_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 val)
 	if (addr >= dev->phy_port_cnt)
 		return 0;
 
-	/* No gigabit support.  Do not write to this register. */
-	if (!dev->info->gbit_capable[addr] && reg == MII_CTRL1000)
-		return -ENXIO;
-
 	return ksz_pwrite16(dev, addr, 0x100 + (reg << 1), val);
 }