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: NKarol Swietlicki <magotari@gmail.com>
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>