net: fsl: Allow most drivers to be built with COMPILE_TEST

There are only a handful of Freescale Ethernet drivers that don't
actually build with COMPILE_TEST:

* FEC, for which we would need to define a default register layout if no
  supported architecture is defined

* UCC_GETH which depends on PowerPC cpm.h header (which could be moved
  to a generic location)

* GIANFAR needs to depend on HAS_DMA to fix linking failures on some
  architectures (like m32r)

We need to fix an unmet dependency to get there though:
warning: (FSL_XGMAC_MDIO) selects OF_MDIO which has unmet direct
dependencies (OF && PHYLIB)

which would result in CONFIG_OF_MDIO=[ym] without CONFIG_OF to be set.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/Kconfig

@@ -8,7 +8,7 @@ config NET_VENDOR_FREESCALE
 	depends on FSL_SOC || QUICC_ENGINE || CPM1 || CPM2 || PPC_MPC512x || \
 		   M523x || M527x || M5272 || M528x || M520x || M532x || \
 		   ARCH_MXC || ARCH_MXS || (PPC_MPC52xx && PPC_BESTCOMM) || \
-		   ARCH_LAYERSCAPE
+		   ARCH_LAYERSCAPE || COMPILE_TEST
 	---help---
 	  If you have a network (Ethernet) card belonging to this class, say Y.
 
@@ -65,6 +65,7 @@ config FSL_PQ_MDIO
 config FSL_XGMAC_MDIO
 	tristate "Freescale XGMAC MDIO"
 	select PHYLIB
+	depends on OF
 	select OF_MDIO
 	---help---
 	  This driver supports the MDIO bus on the Fman 10G Ethernet MACs, and
@@ -85,6 +86,7 @@ config UGETH_TX_ON_DEMAND
 
 config GIANFAR
 	tristate "Gianfar Ethernet"
+	depends on HAS_DMA
 	select FSL_PQ_MDIO
 	select PHYLIB
 	select CRC32