skge: make support for old Genesis chips optional

The GENESIS boards are really old PCI-X boards that are rare.
Marvell has dropped support for this hardware and there is no reason
for most users to have to have this code.

Rather than riddling code with ifdef's make one macro and let
the compiler do the dead code elimination.  This saves about 15%
of the text size.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -2303,6 +2303,15 @@ config SKGE_DEBUG
 
 	  If unsure, say N.
 
+config SKGE_GENESIS
+       bool "Support for older SysKonnect Genesis boards"
+       depends on SKGE
+       help
+         This enables support for the older and uncommon SysKonnect Genesis
+	 chips, which support MII via an external transceiver, instead of
+	 an internal one. Disabling this option will save some memory
+	 by making code smaller. If unsure say Y.
+
 config SKY2
 	tristate "SysKonnect Yukon2 support"
 	depends on PCI