um: -include user.h for USER_OBJ, trim includes

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/os-Linux/elf_aux.c

@@ -12,7 +12,6 @@
 #include "init.h"
 #include "elf_user.h"
 #include "mem_user.h"
-#include <kern_constants.h>
 
 typedef Elf32_auxv_t elf_auxv_t;