[NET]: move config options out to individual protocols

Move the protocol specific config options out to the specific protocols.
With this change net/Kconfig now starts to become readable and serve as a
good basis for further re-structuring.

The menu structure is left almost intact, except that indention is
fixed in most cases. Most visible are the INET changes where several
"depends on INET" are replaced with a single ifdef INET / endif pair.

Several new files were created to accomplish this change - they are
small but serve the purpose that config options are now distributed
out where they belongs.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ipvs/Kconfig b/net/ipv4/ipvs/Kconfig
index 63a82b4..c9820bf 100644
--- a/net/ipv4/ipvs/Kconfig
+++ b/net/ipv4/ipvs/Kconfig
@@ -2,11 +2,11 @@
 # IP Virtual Server configuration
 #
 menu	"IP: Virtual Server Configuration"
-	depends on INET && NETFILTER
+	depends on NETFILTER
 
 config	IP_VS
 	tristate "IP virtual server support (EXPERIMENTAL)"
-	depends on INET && NETFILTER
+	depends on NETFILTER
 	---help---
 	  IP Virtual Server support will let you build a high-performance
 	  virtual server based on cluster of two or more real servers. This