uml: delete some unused headers

Robert Day noticed a few unused headers in UML, so this gets rid of them.

Cc: "Robert P. J. Day" <rpjday@crashcourse.ca>
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/include/misc_constants.h

-#ifndef __MISC_CONSTANT_H_
-#define __MISC_CONSTANT_H_
-
-#include <user_constants.h>
-
-#endif

arch/um/include/signal_kern.h

-/* 
- * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
- * Licensed under the GPL
- */
-
-#ifndef __SIGNAL_KERN_H__
-#define __SIGNAL_KERN_H__
-
-extern int have_signals(void *t);
-
-#endif
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */

arch/um/include/skas/mode-skas.h

-/*
- * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
- * Licensed under the GPL
- */
-
-#ifndef __MODE_SKAS_H__
-#define __MODE_SKAS_H__
-
-extern void kill_off_processes_skas(void);
-
-#endif