net: dsa: restrict SMSC_LAN9303_I2C kconfig

Since kconfig 'select' does not follow dependency chains, if symbol KSA
selects KSB, then KSA should also depend on the same symbols that KSB
depends on, in order to prevent Kconfig warnings and possible build
errors.

Change NET_DSA_SMSC_LAN9303_I2C and NET_DSA_SMSC_LAN9303_MDIO so that
they are limited to VLAN_8021Q if the latter is enabled. This prevents
the Kconfig warning:

WARNING: unmet direct dependencies detected for NET_DSA_SMSC_LAN9303
  Depends on [m]: NETDEVICES [=y] && NET_DSA [=y] && (VLAN_8021Q [=m] || VLAN_8021Q [=m]=n)
  Selected by [y]:
  - NET_DSA_SMSC_LAN9303_I2C [=y] && NETDEVICES [=y] && NET_DSA [=y] && I2C [=y]

Fixes: 430065e2 ("net: dsa: lan9303: add VLAN IDs to master device")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Vladimir Oltean <olteanv@gmail.com>
Cc: Juergen Borleis <jbe@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Mans Rullgard <mans@mansr.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/Kconfig

@@ -72,7 +72,6 @@ source "drivers/net/dsa/realtek/Kconfig"
 
 config NET_DSA_SMSC_LAN9303
 	tristate
-	depends on VLAN_8021Q || VLAN_8021Q=n
 	select NET_DSA_TAG_LAN9303
 	select REGMAP
 	help
@@ -82,6 +81,7 @@ config NET_DSA_SMSC_LAN9303
 config NET_DSA_SMSC_LAN9303_I2C
 	tristate "SMSC/Microchip LAN9303 3-ports 10/100 ethernet switch in I2C managed mode"
 	depends on I2C
+	depends on VLAN_8021Q || VLAN_8021Q=n
 	select NET_DSA_SMSC_LAN9303
 	select REGMAP_I2C
 	help
@@ -91,6 +91,7 @@ config NET_DSA_SMSC_LAN9303_I2C
 config NET_DSA_SMSC_LAN9303_MDIO
 	tristate "SMSC/Microchip LAN9303 3-ports 10/100 ethernet switch in MDIO managed mode"
 	select NET_DSA_SMSC_LAN9303
+	depends on VLAN_8021Q || VLAN_8021Q=n
 	help
 	  Enable access functions if the SMSC/Microchip LAN9303 is configured
 	  for MDIO managed mode.