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/drivers/mconsole_kern.c

@@ -741,7 +741,6 @@ void mconsole_stack(struct mc_request *req)
 {
 	char *ptr = req->request.data;
 	int pid_requested= -1;
-	struct task_struct *from = NULL;
 	struct task_struct *to = NULL;
 
 	/*
@@ -763,8 +762,6 @@ void mconsole_stack(struct mc_request *req)
 		return;
 	}
 
-	from = current;
-
 	to = find_task_by_pid(pid_requested);
 	if ((to == NULL) || (pid_requested == 0)) {
 		mconsole_reply(req, "Couldn't find that pid", 1, 0);