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

arch/um/drivers/chan_user.c

arch/um/drivers/cow_sys.h

arch/um/drivers/daemon_user.c

arch/um/drivers/fd.c

arch/um/drivers/harddog_user.c

arch/um/drivers/mconsole_user.c

arch/um/drivers/net_user.c

arch/um/drivers/pcap_user.c

arch/um/drivers/port_user.c

arch/um/drivers/pty.c

arch/um/drivers/slip_user.c

arch/um/drivers/slirp_user.c

arch/um/drivers/tty.c

arch/um/drivers/ubd_user.c

arch/um/drivers/umcast_user.c

arch/um/drivers/vde_user.c

arch/um/drivers/xterm.c

arch/um/kernel/skas/clone.c

arch/um/os-Linux/aio.c

arch/um/os-Linux/drivers/ethertap_user.c