fs: fix incorrect lflags value in the move_mount syscall

fs: fix incorrect lflags value in the move_mount syscall

The lflags value used to look up from_path was overwritten by the one used
to look up to_path.

In other words, from_path was looked up with the wrong lflags value. Fix it.

Fixes: f9fde814de37 ("fs: support getname_maybe_null() in move_mount()")
Signed-off-by: Yuntao Wang <yuntao.wang@linux.dev>
Link: https://lore.kernel.org/20250811052426.129188-1-yuntao.wang@linux.dev
[Christian Brauner <brauner@kernel.org>: massage patch]
Signed-off-by: Christian Brauner <brauner@kernel.org>