uml: remove duplicate config symbol and unused file and variables

Fix the repetition of the NET symbol.  It was once in UML specific options and
once in networking.  I removed the first occurrence, as it makes more sense to
me to keep it only in networking.

It also removes a mostly empty file which is not used anymore and some
unused variables.

Signed-off-by: Karol Swietlicki <magotari@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/Kconfig

@@ -95,23 +95,6 @@ config LD_SCRIPT_DYN
 	default y
 	depends on !LD_SCRIPT_STATIC
 
-config NET
-	bool "Networking support"
-	help
-	  Unless you really know what you are doing, you should say Y here.
-	  The reason is that some programs need kernel networking support even
-	  when running on a stand-alone machine that isn't connected to any
-	  other computer. If you are upgrading from an older kernel, you
-	  should consider updating your networking tools too because changes
-	  in the kernel and the tools often go hand in hand. The tools are
-	  contained in the package net-tools, the location and version number
-	  of which are given in <file:Documentation/Changes>.
-
-	  For a general introduction to Linux networking, it is highly
-	  recommended to read the NET-HOWTO, available from
-	  <http://www.tldp.org/docs.html#howto>.
-
-
 source "fs/Kconfig.binfmt"
 
 config HOSTFS