selftests/move_mount_set_group:Make tests build with old libc

selftests/move_mount_set_group:Make tests build with old libc

Replace SYS_<syscall> with __NR_<syscall>.  Using the __NR_<syscall>
notation, provided by UAPI, is useful to build tests on systems without
the SYS_<syscall> definitions.

Replace SYS_move_mount with __NR_move_mount

Similar changes: commit 87129ef13603 ("selftests/landlock: Make tests build with old libc")

Acked-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Hu.Yadi <hu.yadi@h3c.com>
Link: https://lore.kernel.org/r/20240111113229.10820-1-hu.yadi@h3c.com
Reviewed-by: Berlin <berlin@h3c.com>
Suggested-by: Jiao <jiaoxupo@h3c.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>