net: Fix sungem_phy sharing.

Since sungem_phy is used by multiple, unrelated, drivers make it
build as a real module under drivers/net.

depmod will pick up the symbol dependency and make sure sungem_phy.ko
gets loaded any time sungem.ko or spider_net.ko is loaded.

Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 31d8792..ef6b6be 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -186,6 +186,9 @@
 
 source "drivers/net/phy/Kconfig"
 
+config SUNGEM_PHY
+	tristate
+
 #
 #	Ethernet
 #