copyin & copyout now return EFAULT and all callers uniformly

copyin & copyout now return EFAULT and all callers uniformly
return (or ignore) this value

SCCS-vsn: sys/kern/kern_descrip.c 5.21
SCCS-vsn: sys/kern/kern_proc.c 4.56
SCCS-vsn: sys/kern/kern_prot.c 5.14
SCCS-vsn: sys/kern/kern_resource.c 4.19
SCCS-vsn: sys/kern/kern_time.c 5.13
SCCS-vsn: sys/kern/sys_generic.c 5.29
SCCS-vsn: sys/kern/uipc_syscalls.c 4.39
SCCS-vsn: sys/kern/vfs_syscalls.c 4.46
SCCS-vsn: sys/ufs/ffs/ffs_vnops.c 4.46
SCCS-vsn: sys/ufs/ffs/ufs_vnops.c 4.46
SCCS-vsn: sys/ufs/lfs/lfs_vnops.c 4.46
SCCS-vsn: sys/ufs/ufs/ufs_vnops.c 4.46
SCCS-vsn: sys/kern/vfs_xxx.c 4.4
SCCS-vsn: sys/kern/uipc_mu_msg.c 4.3