net: dsa: Drop OF dependency for BCM_SF2

NET_DSA_BCM_SF2 does not need to depend on CONFIG_OF anymore since we have
stubs when that option is disabled.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/Kconfig

@@ -5,7 +5,7 @@ source "drivers/net/dsa/b53/Kconfig"
 
 config NET_DSA_BCM_SF2
 	tristate "Broadcom Starfighter 2 Ethernet switch support"
-	depends on HAS_IOMEM && NET_DSA && OF_MDIO
+	depends on HAS_IOMEM && NET_DSA
 	select NET_DSA_TAG_BRCM
 	select FIXED_PHY
 	select BCM7XXX_PHY