print_dirfd: do not print trailing comma

print_dirfd: do not print trailing comma

It was fine to print trailing comma in print_dirfd until introduction
of a syscall with the last argument being a dirfd.
Now it's time to change print_dirfd.

* open.c (print_dirfd): Do not print comma.
(SYS_FUNC(open)): Print comma after print_dirfd() invocation.
* access.c (SYS_FUNC(faccessat)): Likewise.
* chmod.c (SYS_FUNC(fchmodat)): Likewise.
* execve.c (SYS_FUNC(execveat)): Likewise.
* fanotify.c (SYS_FUNC(fanotify_mark)): Likewise.
* fchownat.c (SYS_FUNC(fchownat)): Likewise.
* file_handle.c (SYS_FUNC(name_to_handle_at)): Likewise.
* link.c (SYS_FUNC(linkat), SYS_FUNC(unlinkat), SYS_FUNC(symlinkat)):
Likewise.
* mknod.c (SYS_FUNC(mknodat)): Likewise.
* move_mount.c (SYS_FUNC(move_mount)): Likewise.
* open_tree.c (SYS_FUNC(open_tree)): Likewise.
* readlink.c (SYS_FUNC(readlinkat)): Likewise.
* renameat.c (decode_renameat): Likewise.
* stat.c (SYS_FUNC(newfstatat)): Likewise.
* stat64.c (SYS_FUNC(fstatat64)): Likewise.
* statx.c (SYS_FUNC(statx)): Likewise.
* utimes.c (SYS_FUNC(futimesat), do_utimensat): Likewise.